My own 'body vs. glass' dilemma

Necronomicon

Recently enough I posted a thread outlining my desire for a new walkabout lens, asking if the Canon 24-70L on a crop sensor body was a good or bad idea. I've seen some good arguments for and against the idea, but lately I've been starting to wonder if my money would be better invested in a new body.

I've been comparing specs between my 40D and the 7D, and I'm starting to think that it represents improvements in areas that I need them most. I frequently find myself in low light situations wishing that I could boost the ISO just a little bit more without compromising IQ - and from what I've read there is a significant step up in performance on the 7D. I'm also quite attracted to the faster frame rate per second, as I tend to take the occasional action shots. The added AF points (19 vs. 9) and a seemingly improved AI servo are big attractions in this regard too. And yeah, somewhat guiltily the pixel-peeper in me is attracted to the higher resolution

But if I upgraded my body it wouldn't remove the glass conundrum, and I'm not sure I can justify the outlay on upgrading both. I feel like I've outgrown the 17-85 - it's as fast as an oil tanker, I often feel limited by the minimum aperture of f4-5.6, and the chromatic abberation drives me mad. If I went down the kit route with the 7D I'd have a choice between the 15-85 or the 18-135, but I've been coming across lukewarm reviews of both.

The two lenses I keep coming back to are the 24-70L and the EF-S 17-55 2.8. I know the latter makes more sense for a cropped sensor, but I'm worried that 55mm isn't long enough. That said, I do have the nifty fifty to satisfy longer reach, but ideally I'd have an all-rounder that I wouldn't need to change often. Even though the 24-70L gives me a maximum width of 38mm, I'm not so sure I'd miss wider focal lengths more than I'd miss those greater than 55mm - and with the same 1.6x crop factor I'd have the same decision to make regardless of which of the two bodies I'm using.

Cheers to anybody who's made it through that ramble - honestly, it's not just gear envy, I really think I could push myself and the hobby further if I made one or both of the above upgrades.

I use a 24-105 f/4 a lot. I chose it over the 24-70 (was better suited to what I shoot; I don't find f/2.8 is all it's cracked up to be).

That lens also has the benefit of being cheaper than the 24-70, so you could save a few euro by getting that instead and keeping the savings for a body upgrade.


I spent a lot of time shooting with a 17-85 and a 20D. About a year using mostly that combo, before I bought the 7D, and then a few months later, the 24-105 (so for a while I was using the 7D with the 17-85).

I liked the 17-85 and I was happy with it. Great general purpose lens (I find that the wider end is used more than the zoom end on a walkaround lens). When I went from 17-85 to 24-105 I didn't notice a huge difference to be honest (though I always feel it takes a little bit of time to adjust to a new lens). I wasn't blown away by the L glass that I'd heard so much about.


However, looking back at older photos now, having been using the 24-105 a lot, I do see where the 17-85 had it's problems. The 24-105 is definitely a crisper/sharper image, there's no doubt about it.

I still have my 20D. I use it as a back up. After having been using the 7D for about 8 months straight now, and rarely ever putting it down, I thought I'd pick up the 20D and wonder how I ever managed to get by with it. So I took the 20D out for a walk the other day and I could easily live with it. It's an amazing camera. The only downside is the tiny LCD on the back (though I believe the 40D has a larger LCD?).


So, with my own personal experience in my mind, if you must upgrade, I'd go with lens first. I'd definitely recommend changing body if I thought you would improve upon what you have significantly, but truth be told, I think if you bought the body now you'd still be annoyed with not having the lens.

That said, the 40D is supposed to be better than the 20D, and the 20D is still a top class camera in my opinion, so if I were you I'd pick up the 24-70/105 (whichever you prefer) and instead of picking up the 7D, I'd instead go with an L zoom (especially if you're doing "action" stuff? By that I presume you mean sports?). 70-200 f/4 can be gotten for feck all these days. €400 or so second hand?

I think that'd be the way to go if I were being honest. The biggest problems I had with the 20D and the reason I wanted to upgrade in the first place was because I was dealing with tricky lighting and lots of people a lot of the time, and the screen size made it difficult for me to ensure that I had the right person/people in focus in certain photos. The 7D's screen is a huge improvement for me here.

If someone could put a larger screen on my 20D I'd still be using it regularly. The 40D has a larger screen anyway, so I don't think you'd really need the upgrade to be honest (though again, I can't stress enough that everyone has different types of photography in their head and everyone approaches things differently, so it very well may be a case where the camera body would benefit you more, especially if you really, really need that faster buffer and FPS. I can only give you my recommendations based on my own personal experience).


Also, I'd google around to see ISO comparisons between the 7D and 40D. 7D is great at noise handling, but how often will you really need it?


I shot this last night at f/4 at ISO 12,800 (another reason I don't bother with 2.8 lenses, though I'd recommend having a fast prime anyway). It was a pitch black street, and the photo, although definitely noisy, is perfectly usable in my opinion;





Full size;

http://photos3.pix.ie/99/6E/996EFB03C6DE4F43AA1DDDE0B58FEE56-0000333410-0002718934-05184L-FD68B3B13D664C4786099FA230981CEB.jpg


At 2.8 I could've shot that at 6,400 ISO. It'd have made feck all difference. Just pointing this out to you to throw the 24-105 into your viewfinder ( :pac: ) incase you had overlooked it when you decided on the 24-70 f/2.8. That said, I suppose the 2.8 could be handy if the 40D's ISO handling is really bad, but otherwise I wouldn't be too bothered.


That's just me personally though. It's your decision at the end of the day

Keep us informed whatever you decide to do though

Necronomicon

Interesting that you haven't particularly missed the wider focal lengths since upgrading from the 17-85. One reason I'm still leaning for the 24-70 is because I could keep the 17-85 and maybe think about getting a 10-22 or something in the future for wider stuff (the Sigma version is very reasonble).

Food for thought though, cheers for the lengthy reply

Necronomicon

Interesting that you haven't particularly missed the wider focal lengths since upgrading from the 17-85.[/quote]

Oh, I have. I picked up a 10-20 Sigma f/4-5.6 shortly after the 24-105. 24 isn't very wide on a crop body (though it has it's small upside in that you know you'll be able to shoot at it's widest without any real fear of distortion at all, which the 17-85 has a bit of at it's widest angle).

Necronomicon wrote: »

One reason I'm still leaning for the 24-70 is because I could keep the 17-85 and maybe think about getting a 10-22 or something in the future for wider stuff (the Sigma version is very reasonble).

I find that mentality a tad confusing... You'd rather get the 24-70, and also onto the 17-85? Surely, from a focal length standpoint, you'd be better off getting the 24-105, and selling the 17-85 to fund a wider lens (Sigma 10-20, Canon 10-22, etc.)?

Financially you'd save money doing that, and cover a wider focal range (albeit with a slower short zoom lens)?

Maybe I read it wrong?

Necronomicon

Deleted User wrote: »

I find that mentality a tad confusing... You'd rather get the 24-70, and also onto the 17-85? Surely, from a focal length standpoint, you'd be better off getting the 24-105, and selling the 17-85 to fund a wider lens (Sigma 10-20, Canon 10-22, etc.)?

Financially you'd save money doing that, and cover a wider focal range (albeit with a slower short zoom lens)?

Maybe I read it wrong?

That is a valid point - I left out one very important piece of information though, the 17-85 has occasionally been giving me the dreaded '101err' message lately, so thoughts of selling it hadn't even entered my head. So my thinking is I could just hold onto it for the very odd landscape until my wallet recovered and I could pick up a 10-20. If I was going for one of the L zooms I'd probably opt for the 24-70, I use 2.8 quite a bit on my 50mm and 100mm primes.

Pete67

Just one point that hasn't been mentioned yet - the 24-70 being a faster lens gives you more options if controlling depth of field is important to you. This may be more useful than the 1 stop speed advantage.

hbr

Necronomicon wrote: »

I've been comparing specs between my 40D and the 7D, and I'm starting to think that it represents improvements in areas that I need them most. I frequently find myself in low light situations wishing that I could boost the ISO just a little bit more without compromising IQ

The problem is that the 18MP sensor in the 7D is only slightly
better at high ISO than the 10MP sensor in the 40D. The newer
cameras claim to support ISO 6400 and 12,800, but in reality
ISO expansion is carefully hidden away in the custom function
menus, just in case you might make the mistake of actually
using it.

- and from what I've read there is a significant step up in performance on the 7D. I'm also quite attracted to the faster frame rate per second, as I tend to take the occasional action shots.

The 7D is very fast. But the increment in shooting speed is not that
great compared to the 40D.

The added AF points (19 vs. 9) and a seemingly improved AI servo are big attractions in this regard too. And yeah, somewhat guiltily the pixel-peeper in me is attracted to the higher resolution

I never understood the need for the ever increasing number of AF points.
It seems to me that the more you have, the greater the chance of focusing
on the wrong place unless focus point selection is heavily weighted in favour
of the centre point. I usually use centre point only on my 50D.

If I went down the kit route with the 7D I'd have a choice between the 15-85 or the 18-135, but I've been coming across lukewarm reviews of both.

The 15-85mm is an excellent lens, but they are quite pricey. The 18-135mm
is not in the same class, but the ones bundled with recent 7D kits seem quite
good. I have one if you want to try it before you decide. These were taken with
the 18-135mm:

http://pix.ie/corkpix/2381781
http://pix.ie/corkpix/2156627
http://pix.ie/corkpix/2277485
http://pix.ie/corkpix/2248442

The two lenses I keep coming back to are the 24-70L and the EF-S 17-55 2.8. I know the latter makes more sense for a cropped sensor, but I'm worried that 55mm isn't long enough.

Choices, choices... IMO, 55mm isn't long enough and 24mm isn't wide enough.
The 15-85mm scores well here. The Sigma 17-70mm is also worth considering.
My brother just bought the 17-55mm. I haven't had a chance to play with it yet.
By all accounts, it is an excellent lens. Another star performer in this FL range
is the Tamron 17-50mm f/2.8. (non-stabilised version). I also have this lens if
you want to try it.
http://pix.ie/corkpix/album/416187

Cheers to anybody who's made it through that ramble - honestly, it's not just gear envy, I really think I could push myself and the hobby further if I made one or both of the above upgrades.

There is nothing quite like a nice new toy. I would buy a 7D if I could afford it.
Like you, I would have to justify my purchasing decision by asking if it would
take better pictures than my current 50D and 500D which are about equal in
terms of image quality. I think the honest answer is probably no.

Based on everything you have said, I think you have several options.

1 Do nothing. You are getting some great shots from the 40D.

2 Buy a new lens. 15-85 or 17-55 would be affordable if you don't buy a 7D.

3 Buy a 60D which would match the 7D for IQ and high ISO.

4 To hell with the cost. Buy a 7D and a few L lenses.

5 Wait for the 7D mkII

The Canon 18MP sensor is now three years old. It is still a good
performer, but the Sony sensors used in Nikon, Pentax and Sony
DSLRs are now slightly better in terms of noise and dynamic range.
Canon will want to close this gap as soon as possible.

Necronomicon

That's a tremendously helpful post, much appreciated. And thanks for the offer to let me try the glass! Plenty of food for thought, thanks all.

FoxT

Hi Steve!

Like yourself I have a 40D, but my personal choice would be a 5DII body & keep the 40D for the following reasons:

1 - the 40D has plenty AF points, AF speed, AF accuracy, and continuous frame rate for sports, especially if you only do it occasionally.

2 - IMO the 7d ( which is, to be fair, a v. nice camera) has improvements in these areas which look good on paper but which I really doubt will make much of a difference in terms of photos taken.

3 - The 5D mkII at 3200 ISO is about as good as the 40D on 800. (This is not at all scientific, just my opinion from taking about 100-150 shots at a wedding last year on one)

4 - having both an FF & a 1.6 crop body gives you the best of all possible worlds

5 - Keep your existing lens stock for now, you will get great mileage from the 5D & the 50mm + 100mm macro you have.


Drawbacks are:
- you can't use EF-S lenses with the 5D II (or any canon FF) as far as I know
- cost
- lug 2 bodies around
- 5DII RAW files are big, about 25MB, think big flash cards, maybe faster PC....
- 5DII has no in-camera flash. I use the 40D flash quite a bit for fill-in, esp on sunny days, is very handy.

Benefits are
- Immediate 2-stop benefit with 5D II, which is huge. Versus small incremental benefits for the 7D.
- the 5D II will keep you going for a long time (just as I think the 40D will) . There will be improvements in new bodies of course - but both these cameras are sooo good that IMO it will be a long time before a new camera comes out that is say worth eu1000 more.


and other stuff...

If you like the reach of longer focal lengths ( greater than 100mm say), L telephotos for the 5D II become hugely expensive & also a logistical exercise. the 70-200mm f/2.8 on the 5DII = 100-320mm on the 40D in terms of reach....and IMO its a short-ish lens a lot of the time! You can make up a bit by cropping heavily - but the bottom line is that even if 400mm f/2.8 was in your budget, you are looking at an item that Ryanair will probably charge you eu50 per flight leg, that barely fits into the boot of your car, that you'll eventually pop a bollock from lugging it around, etc. etc.


Phew! sorry this is so long, didnt have time to write a shorter one.

-FoxT

FoxT

FoxT wrote: »

3 - The 5D mkII at 3200 ISO is about as good as the 40D on 800. (This is not at all scientific, just my opinion from taking about 100-150 shots at a wedding last year on one)

Benefits are
- Immediate 2-stop benefit with 5D II, which is huge. Versus small incremental benefits for the 7D.

This is actually something I would contest. I'm assuming you're saying that ISO on the 5DII is significantly better than the 7D, which I don't think is true.


When I bought the 7D, it was a long, drawn out process, as I weighed it up against the 5DII over and over again. Lots of online searching gave me ISO tests from both cameras, etc. and I found that the difference in terms of noise handling ability was negligible.


This thread is very interesting;

http://photography-on-the.net/forum/showthread.php?t=930196

hbr

The dpreview studio shot comparison tool is a great way of
evaluating the high ISO performance of cameras. It is best
to use the RAW rather than JPEG shots because in camera
processing of JPEGs will probably include some form of noise
reduction. This makes images look less noisy, but it also tends
to destroy fine detail.

http://www.dpreview.com/reviews/canoneos60D/page19.asp

The 40D is not on the list of tested cameras. The 1000D which
uses an identical (or at least very similar) 10MP sensor compares
very well with the 50D, 60D, 7D and even the 5D II up to it's maximum
ISO setting of 1600.

The 5D II has a visible advantage at ISO settings above 3200. At
lower ISO settings, there is little to choose between any of them.

Borderfox

The one constant I have had while working has been the glass I bought when I started, on the choice front you would have a huge improvement in the 17-55 f2.8 IS even with the 40d body.

FoxT

Thanks KKV for the interesting link - I agree, while the 5DII has better high ISO performance, the difference between it & the 7D is not huge - it looks like about 1 stop or so to me. Clearly the 7D is a good jump ahead of the 40D at high ISO!

As a 40D owner then, given the choice between


17-55 f/2.8
or
24-70L f/2.8
or
7D

... I'd find myself having to decide first if I ever wanted a FF body.

If the answer is 'no' then I'd go for the 17-55. ( not much difference between 55m & 70mm - you can always shoot at 55 & then crop!)

If the answer is 'yes', then I'd save a bit more & get the 5DII.

If the answer is 'maybe I dont know' then I'd go for the 17-55 & forget about FF, the plan being to get a 7D down the track..
(My logic here is that I'll never spend the guts of eu2k on a FF body if I am not sure I want one!)

Necronomicon

Thanks for the added replies everyone, I'm still researching and thinking - probably too much, there will come a point when I just have to take the plunge!

@FoxT I could probably just about stretch to the 5DII but I just don't think I could justify it when I reflect on what it would be used for - I don't think I have any business owning one (just yet!) You raise a valid point about buying EF-S if I have aspirations of owning a FF body one day (I'd like to think I will) but at least Canon gear holds its value well, and the 17-55 is a very well regarded lens so hopefully I'd get a decent enough return on it.

I certainly am leaning towards keeping the 40D, I've been out a bit with it lately and I'm still happy with the results I'm getting when I have my preferred glass on it - I think I've narrowed the search down to replacing the 17-85. I've come quite close to pulling the trigger on the 17-55 2.8, but I just want to be sure in my mind that it's long enough. The nifty fifty would probably compliment it well, but the less lens changing I'm doing the better.

Borderfox

The 85mm f1.8 would be a good compliment to the 17-55, the 50mm would be covered in the zoom

Necronomicon

Borderfox wrote: »

The 85mm f1.8 would be a good compliment to the 17-55, the 50mm would be covered in the zoom

I was thinking more in terms of effective focal lengths, i.e. the 50mm being 80mm on a 1.6 crop. Though I'm a bit confused now, do APS-C bodies have the same crop factor on EF-S lenses as they do on EF? I was always under the impression that EF-S were designed to compensate for the crop factor, so the 17-55 is actually 17-55mm.

FoxT

On the same camera body/sensor size, a 50mm EF-S lens will have the same angle of view as a 50mm EF lens.

The 'crop factor' is a function of sensor size.

If the EF-S was compensated for crop factor , the only way to do that is to change the focal length!

The 17-55 is actually 17-55 - all millimeters are the same!

Cheers ,

FoxT

Necronomicon

Necronomicon wrote: »

I was thinking more in terms of effective focal lengths, i.e. the 50mm being 80mm on a 1.6 crop. Though I'm a bit confused now, do APS-C bodies have the same crop factor on EF-S lenses as they do on EF? I was always under the impression that EF-S were designed to compensate for the crop factor, so the 17-55 is actually 17-55mm.

The focal length written on all lenses is the focal length as it would be on a 35mm film camera/full frame sensor, as far as I am aware.

So regardless of whether the lens is EF or EF-S, the focal length written on the box is the focal length as it'd be on full frame.

So, for example, if you go out and buy an EF-S 85mm 1.8 and an EF 24-105, if you put them both on a crop sensor camera at the same focal length, you'll get the exact same image.

If you put them both on a full frame sensor, then, again, you will have exactly the same field of view (I'm aware you can't put an EF-S on a full frame, but just for example's sake).



That's as far as I know anyway (though I'm always happy to be wrong).

DaireQuinlan

Deleted User wrote: »

The focal length written on all lenses is the focal length as it would be on a 35mm film camera/full frame sensor, as far as I am aware.

The focal length written on all lenses is the focal length of the lens. That's pretty much it right there, it has nothing to do with what format the camera is.

Necronomicon

Sorry guys, I'm still confused. What I'm saying is when you put an EF lens on an cropped body, it effectively gives you a different focal length - i.e. the 24-70 gives you a 38-122mm field of view on a 1.6 body. I was always under the impression that EF-S lenses were designed to negate the crop factor of APS-C bodies, so that you get the 'proper' focal length of the lens. So the 17-55, for example, wouldn't be cropped to 27-88mm on a 1.6 cropped body.

Was I wrong?

DaireQuinlan

Necronomicon wrote: »

Was I wrong?

Yes. 17mm is 17mm is 17mm. My 50mm bronica lens has a focal length of 50mm on the (medium format) bronica, a focal length of 50mm if I were to mount it on one of my 35mm film bodies, and 50mm if I stuck it on the front of some cropped sensor digital body.

DaireQuinlan

DaireQuinlan wrote: »

The focal length written on all lenses is the focal length of the lens. That's pretty much it right there, it has nothing to do with what format the camera is.

True, but that doesn't actually mean anything. A crop sensor is a crop sensor regardless of what lens is connected. A front door key is a front door key, regardless of what front door it's in.



It's when the two come together that the confusion and crop factors come into play.

If a lens is EF-S then you always multiply the crop factor. That is, a Canon 10mm EF-S prime is 16mm when you clip it onto the (1.6 crop sensor) camera body.

Regardless of the brand, make or mount of the camera, the numbers on the side of the lens are written as though they were intended for a full frame camera (even though an EF-S was never made to fit a full frame body).


For example, the widest lens you can buy in EF form is a 16-35. The widest EF-S you can buy is 10-22. At their widest, on their respective cameras (EF on full frame and EF-S on 1.6 crop sensor) they both have the same angle of view. Despite the 10mm clearly having a shorter number on the side, and even though it's going on a crop sensor that it was made for, you still multiply it anyway.

(those aren't the widest you can get, but again, just examples).


As I say, I'm open to correction, but I'm fairly certain that's how it works.


EDIT: Listen to the first 30 seconds of this video.

http://www.youtube.com/watch?v=37qNBit9dlI

Kenny Logins

As I understand it the focal length does not (can not) change when moving from full frame to crop, but people often refer to, or compare, the resultant images in focal length terms, which just confuses the issue.

DaireQuinlan

DaireQuinlan wrote: »

Yes. 17mm is 17mm is 17mm

Except when you put it on a crop sensor. Yes, the focal length of the lens is still the same, but the effective focal length changes.

A 17mm on a crop sensor will get you closer to the action than a 17mm on a full frame. That's the heart of the argument here.

(As i say, always happy to be shown to be wrong, but I'm fairly certain that's how things operate!)

DaireQuinlan

Deleted User wrote: »

If a lens is EF-S then you always multiply the crop factor. That is, a Canon 10mm EF-S prime is 16mm when you clip it onto the (1.6 crop sensor) camera body.

It's not, it's a 10mm lens.

Regardless of the brand, make or mount of the camera, the numbers on the side of the lens are written as though they were intended for a full frame camera

No they're not, the number on the side of the lens is the focal length of the lens, it's not 'written as though they were intended' for anything.

Take that example I quote above of the 50mm bronica lens. It's a moderate wideangle on medium format, a normal lens on a 35mm film body, and a short telephoto on a crop body or APS camera. The lens remains a 50mm through-out though.

DaireQuinlan

DaireQuinlan wrote: »

It's not, it's a 10mm lens.



No they're not, the number on the side of the lens is the focal length of the lens, it's not 'written as though they were intended' for anything.

Take that example I quote above of the 50mm bronica lens. It's a moderate wideangle on medium format, a normal lens on a 35mm film body, and a short telephoto on a crop body or APS camera. The lens remains a 50mm through-out though.

Right then, to put an end to going around in circles... your 50mm lens; what's it's effective focal length on a Canon 7D?

Necronomicon

I see what you're saying Daire, that the focal length of a lens doesn't change regardless of format. But the field of view does change as you allude to in your example - the 50mm is a moderate wide angle on a medium format body and a short telephoto on a cropped sensor body. What I'm trying to figure out is if the crop effect of an APS-C body applies to EF-S lenses in the same way it affects the field of view of an EF lens.

Necronomicon

Necronomicon wrote: »

What I'm trying to figure out is if the crop effect of an APS-C body applies to EF-S lenses in the same way it affects the field of view of an EF lens.

Yes. It's quickly overviewed in the video linked to above where the reviewer explains that the EF-S lens offers a different focal range on a crop sensor.

Adrian.Sadlier

Necronomicon wrote: »

I see what you're saying Daire, that the focal length of a lens doesn't change regardless of format. But the field of view does change as you allude to in your example - the 50mm is a moderate wide angle on a medium format body and a short telephoto on a cropped sensor body. What I'm trying to figure out is if the crop effect of an APS-C body applies to EF-S lenses in the same way it affects the field of view of an EF lens.

As I understand it (I'm a Nikon shooter) an EF-S lens will only work on an APS-C sensor. An EF lens will work on an APS-C sensor and full frame.

The focal length of a lens does not change whether you put it on an APS-C or full frame sensor.

The difference between EF-S and EF (besides price) is that an EF-S lens is designed to work with the smaller APS-C sensor and doe not have a wide enough aperature (opening) to fully expose a full frame sensor.

The video at this link http://gizmodo.com/5655089/the-difference-between-a-full+frame-sensor-and-the-one-inside-your-camera shows the difference well.

DaireQuinlan

Deleted User wrote: »

Right then, to put an end to going around in circles... your 50mm lens; what's it's effective focal length on a Canon 7D?

Why bother with all this 'effective focal length' nonsense though ? It's at best meaningless and at worst gives rise to all sorts of confusion. Look at those queries above about whether the focal length is given 'with the crop factor in mind' or whether the crop factor 'applies'to ef and efs lenses (or whatever the terminology is).
People successfully used all sorts of lenses on all sorts of formats for years without resorting to this sort of confusing marketing led sophistry.
In answer to your question, I'd anticipate it being a short telephoto, and I'd have to shoot it a bit and get used to the FOV and how it shot before being really comfortable with it.

DaireQuinlan

DaireQuinlan wrote: »

Why bother with all this 'effective focal length' nonsense though ? It's at best meaningless and at worst gives rise to all sorts of confusion. Look at those queries above about whether the focal length is given 'with the crop factor in mind' or whether the crop factor 'applies'to ef and efs lenses (or whatever the terminology is).
People successfully used all sorts of lenses on all sorts of formats for years without resorting to this sort of confusing marketing led sophistry.
In answer to your question, I'd anticipate it being a short telephoto, and I'd have to shoot it a bit and get used to the FOV and how it shot before being really comfortable with it.

But I don't believe it is meaningless at all. I think it's one of (if not the most) important things to consider when choosing between a full frame or crop sensor camera.

It has an immediate and direct affect on your image. I think the additional 'reach' of a crop sensor is a valuable thing to have and it is something that I considered a positive aspect of the 7D when I was buying it.


When purchasing a camera and up in the air about whether to buy a full frame or crop sensor, I think noise performance and effective focal range are important considerations to make.

Necronomicon

If it wasn't important I'd go out and get a 24-70L without a moment's hesitation.

Put my query this way - will my EF 50mm lens give me the same field of view as an EF-S lens zoomed to 50mm? My understanding was that the image would be cropped using the EF, but not on the EF-S, therefore giving me a wider field of view.

DaireQuinlan

Necronomicon wrote: »

Put my query this way - will my EF 50mm lens give me the same field of view as an EF-S lens zoomed to 50mm? .

I can't think of many more ways to say this, but yes, yes it will. The focal length of the lens is 50mm. 50mm is the focal length of the lens. 50mm = 50mm. So assuming they're mounted on bodies of similar format, they will have the same FOV.

FoxT

From a photographers point of view, the focal length of a lens is an indicator of the angle of view, or Field of view.

A telephoto lens will have an angle of view of say 10 degrees or less, a 'normal' lens has an angle of view of about 50 degrees, and a wide angle lens will have an angle of view of 80-150 degrees. (These are approximate).

For reasons unknown to me, camera lens manufacturers have always specified lens' focal lengths & not their angle of view.

Back in the 35 mm film days, everybody just got used to it. On a 35mm camera, everybody 'knew' that 40- 60mm gave 'normal' view angles ( similar to the human eye) with 24mm was wide, 100mm was long, etc.

When digital came along, one thing that happened was that a variety of sensor sizes became available in camera bodies that accepted the same lenses.

If you have a bigger image sensor, then it will always give a wider angle of view than a smaller one, all other parameters being kept equal. For 35mm film camera users transitioning to digital it was desirable to come up with a rule of thumb to explain this. Thus, the 'crop factor' was born.

(Of course, for the growing number of people who never used a 35mm film camera, the 'crop factor' issue is confusing & unhelpful. )


So, when people say that a 50mm lens on say a 7D is 'really' 85mm - this is shorthand for stating the following:


"This lens has a 50mm focal length. The angle of view that it delivers on a 1.6x crop frame sensor is the same angle of view that an 85mm lens will give on a full frame sensor. "


The focal length of a 50mm lens is ALWAYS 50mm - Doesn't matter if it is EF, EF-S, FD, or whatever. But the angle of view varies depending on sensor size.


When designing a lens, one of the factors to consider is the sensor size. All other factors being equal, it is more expensive to make a lens that performs well with larger sensors. The lens needs to be physically larger, because it needs to produce a larger, focused image. ("Image circle")

Another design factor is view angle. A lens that gives a 10 degree angle of view for a crop sensor camera will be smaller & cheaper than a lens that gives a 10 degree angle of view on a 35mm camera.

Here's an example: A 200mm lens gives a 10 degree horizontal angle of view on a full frame sensor.

On a crop frame sensor, you will need (200/1.6)mm for the same effect. This works out at about 135mm.
A 200mm f/2 lens is GBP 5 grand at Wex, while a 135mm f/2 lens is about GBP900


The point? for a given angle of view, telephoto lenses for crop sensor cameras are cheaper and/or faster aperture, and/or physically smaller.

So, Steve , your EF 50mm lens will give you the same field of view ( or view angle, as I have referred to it here) as an EF-S 17-55 set to 50mm, regardless of what camera body you use. (But see warning below)


The EF-S lens is different from an EF lens in the following 2 ways that I know of:

1 - The EF-S lens gives a smaller image circle.
2 - The EF-S lens MAY (some will, I dont know if all do) interfere mechanically with the mirror if you put it on a FF body. This is a bad, bad, thing.

Summary:

For a given camera sensor, & lens focal length the Field of view is always the same.

Lenses designed for crop sensors do not work well on FF bodies, and in some cases may lead to damage.

Lenses designed for FF sensors can be used on crop sensor bodies ( At least on Canon)

Hope that helps!

-FoxT

FoxT

...always the same length, but your field of view will vary depending on the size of your partner's body!

Necronomicon

FoxT wrote:

So, when people say that a 50mm lens on say a 7D is 'really' 85mm - this is shorthand for stating the following:


"This lens has a 50mm focal length. The angle of view that it delivers on a 1.6x crop frame sensor is the same angle of view that an 85mm lens will give on a full frame sensor. "


The focal length of a 50mm lens is ALWAYS 50mm - Doesn't matter if it is EF, EF-S, FD, or whatever. But the angle of view varies depending on sensor size.

Cheers. I think what I was basically imagining was that such a thing as 'cropped lenses' existed, and that's what EF-S were. So using your explanation above, my assumption was:

"This EF-S lens has a 50mm focal length. The angle of view that it delivers on a 1.6x crop frame sensor is the same angle of view that an EF 50mm lens will give on a full frame sensor. "

This was obviously quite incorrect.

Necronomicon

Thanks to everyone for the advice (and for clarifying my incorrect assumptions about EF-S mounts). I just ordered the 17-55 2.8 IS, €826 delivered. Unfortunately the lens hood doesn't come with, so I'll have to think about ordering that soon. There was a definite draw towards owning my first 'L', but the EF-S just makes more sense. Looking forward to posting my first shots.