Lens question - buying a 60D

Christ0pher

Hi all, my question is about ultra wide lenses and small sensor (APS-C) cameras. I am about to buy a Canon 60d, and don't really want to get a kit lens. I'd be happy with a 50mm prime, and I'd like an ultra wide too.
It'll be my first APS-C camera, and this whole crop factor thing has my mind melted. So to my question - are there ultra wide zooms out there designed specifically for APS-C. In other words - can I buy a 10-22mm lens that will actually give me that field of view onto the sensor - no cropping. Also - the prime - is there a 50mm that will get me exactly 50mm onto the sensor, and not 50mmx1.6=80mm ! I find this all so confusing !
And if so - have you any recommendations. My lens budget is about €550.
I don't think I will ever get a full frame camera, at least not for a long time. thanks !

The Doktor

I think I can answer this, as I was in the same boat as you 2 months ago.
Basically the Canon EF-S lenses are designed for the small sensor cameras.
So, if you buy an ultra wide angle EF lens and use it on APS-C camera it will just be wide, but if you use an EF-S ultra wide lens it will be ultra wide on your 60d.
There is a canon EF-S ultra wide lens, the 10-22mm (which I bought, and its ultra wide on the 60D)
http://www.canon.ie/For_Home/Product_Finder/Cameras/EF_Lenses/EF-S/EF-S_10-22mm_f3.5-4.5_USM/

I could be wrong, but im sure somone will be able to answer you better if i am.

Christ0pher

okay - that's interesting. it's a nice lens - but a tad on the pricey side. So EF-S means it's suited to aps-c ? I shall go do some research !

amdgilmore

No, the EF-S lenses don't make any difference to focal length. The effective focal length is the same as any lens used on a crop sensor (ie, the stated focal length multiplied by 1.6). EF-S lenses are just designed to provide better IQ with crop sensors.

You can't match the field of view of a fulll-frame camera when it comes to UW lenses. Once you go lower than 10mm you're usually into fish-eye territory.

edit: except that I've just remembered there is a decent 8-16mm EF-S lens. Made by Sigma. That's about as wide as you're going to get though.


So...

Wide Angles: The Tokina 11-16 f/2.8 is arguably the best ultra wide for an APS-C camera. Nearly as wide as the Canon and with a fixed aperture. You can get one for about half the price of the 10-22 listed above.

edit: and the Sigma, but the trade off is no constant aperture and it only opens to f/4.5. Not a huge deal on a wide-angle lens, I suppose.


Primes: For the equivalent of a 50mm prime on a full frame camera, you'll need to get a lens in the range of 30-35mm.

The 35mm f/2 is well built and relatively cheap (about 350)
If you go for a 50, get either the Canon 1.8 (very cheap, low quality build, but high quality optics) or the 1.4 (less cheap, but very good)

As somebody who owns an APS-C camera and a 50mm lens, I'd recommend going with the 35mm. 50 is just a little bit too close for most photos.

Nobody ever takes that advice though.

Christ0pher

damn damn ! so confusing! I was convinced that the EF-S lenses were optically adjusted to remove the crop factor. (why can't that be done manufacturers??)
Here's a camera labs excerpt which - to me - reads like it removes the crop factor. "since cropped-frame DSLRs aren’t using the full area of normal lenses, many manufacturers additionally offer models which are only corrected for this smaller frame. Canon, Nikon, Sony and Pentax refer to these types of lenses as EF-S, DX, DT and DA respectively. These aren’t suitable for full-frame DSLRs though, so if you’re thinking of upgrading to full-frame in the future, try to avoid these models."
eh?
But Sigma at least clear things up, description about that 8-16mm mentioned above. which is €665 from DigitalRev - pricey
"The Sigma 8-16mm f/4.5-5.6 DC HSM is the first ultra wide zoom lens with a minimum focal length of 8mm, designed especially for cameras with an APS-C size image sensor. This lens has an equivalent angle of view of a 12-24mm lens with an APS-C-sized sensor SLR camera. "

But at least now I know. ALL lenses for APS-C cameras are affected by the crop factor. Thanks to the two responses so far.

The Doktor

Christ0pher wrote: »

damn damn ! so confusing! I was convinced that the EF-S lenses were optically adjusted to remove the crop factor. (why can't that be done manufacturers??)
.

They are.
As previous poster says, focal length is focal length no matter what camera or lens you use. If it says 50mm on it then thats the focal length, cropped sensor or not.
For me the best description is the diagram of the image circle. About 2/3 down this page.
http://www.bobatkins.com/photography/tutorials/crop_sensor_cameras_and_lenses.html

As you can see, if you use an EF lense on a cropped sensor you loose some of the image. If you use an EF-S lens you dont. So as you can imagine if you use a full frame wide lens, you will loose a lot of the advantages the wide lens give you. If you use an EF-S one you dont.

vic20

Here's another explanation of crop factor:
http://www.kenrockwell.com/tech/crop-factor.htm

It does take a bit to get the head around it

pearljamfan

Christ0pher wrote: »

so if you’re thinking of upgrading to full-frame in the future, try to avoid these models."
eh?

the lens wont actually fit on a full frame, ( or is it the other way round..) because of the mirror inside, it doesnt have the space.

i have a 50mm 1.4, love it, but i bought it because i knew it was a good quality lens, not because of the 50. ive managed to do alot with it but wider would be handy for sure , i hear the 15-85mm is as good as an L lens, you could get one 2nd hand for your budget.

Christ0pher

oh God now I am totally lost ! So is this right theoretically.

If I own a full frame sensor body and stick on an EF lens, say 12mm UWA - I see exactly 12mm of ultra wideness. excuse my simple terminology. trying to keep things simple.

But if I then put that same EF lens onto a 60d (aps-c) cam - I see 19.2mm of wideness. (12 x 1.6 = 19.2) So I don't "get" the full wideness of the lens. Right so far?

But now you are saying if I stick a 12mm EF-S onto my 60d - I still see 19.2mm of wideness? Or is that crop factor only present on EF lenses on aps-c bodies?

I need to actually walk into a shop and do this don't I? I have a headache.

pearljamfan

you still see the 19.2 wideness only they are only compatible with eos cameras and not full frame.

amdgilmore

I know it seems confusing, and there's always a lot of extraneous and confusing info given when it comes to crop factors and lenses and sensors. But the long and short of it is this:

No matter what lens you put on an APS-C camera, the 1.6 crop factor is always present. The equivalent focal length will always be 1.6 x stated focal length

There's no way around it. There's no lens that will change it.



Now, just to give a quick explanation of the difference between EF and EF-S. None of the below changes the info in bold, so if you're confused by any of this, just ignore it and read the bit in bold again!


Technically, focal length is always the same. As mentioned above, a 50mm lens is a 50mm lens, whether it's on a crop or a ff. The difference is in how much of the image the sensor can see.

When you use an EF lens on an APS-C body, the lens is transmitting a full frame image to the sensor. But the sensor can only see 60% of that image, and as result the edges of the frame are cropped out.

An EF-S lens on an APS-C body is only transmitting an area equivalent to what the sensor can see. That's it.

This has benefits in terms of image quality, image distortion and lens size (and price). But the equivalent focal length is still 1.6 x the stated focal length.

amdgilmore

And, to give a visual example of what I mean when I say that the EF-S lens is transmitting an area equivalent to what the APS-C sensor can see, this is what an EF-S lens on a Full Frame camera would look like:

http://user.xmission.com/~dgadams/Tests/imgmac090.jpg

Christ0pher

pearljamfan wrote: »

you still see the 19.2 wideness only they are only compatible with eos cameras and not full frame.

It's strange. I don't really see the point of AF-S lenses then. May as well just get EF since they both crop on a APS-C sensor anyhow. I mistakenly thought that EF-S simply "shrunk" the full frame image, corner for corner, onto the smaller sensor. Meaning you get exactly the same image, corner for corner, onto the smaller sensor. To me - that would make sense. but not to the manufacturers it seems.

I'm probably being too pedantic anyway. I mean the difference between a 10mm and a 16mm wide is not really that huge. In the grand scheme of things. Thanks for all the answers. Have a great weekend

edit: yes - I understand ef-s improve quality and are probably cheaper. so I have a lot to think about!

DaireQuinlan

Christ0pher wrote: »

It's strange. I don't really see the point of AF-S lenses then. May as well just get EF since they both crop on a APS-C sensor anyhow. I mistakenly thought that EF-S simply "shrunk" the full frame image, corner for corner, onto the smaller sensor. Meaning you get exactly the same image, corner for corner, onto the smaller sensor. To me - that would make sense. but not to the manufacturers it seems.

You're confusing two mostly unrelated things here. The focal length of a lens is a physical property of the lens. The 'manufacturers' can no more re-label a lens than they can (to put it in digital terms) sell a 6 megapixel camera as a 12 megapixel camera.
The other thing is the effective field of view of the images produced by that lens. That's a function of the camera body that the lens is mounted on. I have a 50mm for my medium format system, which results in wide-angle images. That same 50mm mounted on one of my 35mm film bodies would result in a more standard field of view, and if I stuck it on the front of a APS-C DSLR i'd get a short-telephoto FOV.
Photographers have been blithely dealing with this issue since the dawn of photography (my 300mm for my 8x10 for example is a bit wide of normal) it's only become an issue for some reason since the advent of aps sized dslrs.

edit: yes - I understand ef-s improve quality and are probably cheaper. so I have a lot to think about!

I doubt they 'improve quality' but they're most likely smaller and lighter and cheaper than their cousins with increased coverage.