Boring lens stuff ,sorry.

311

I'm trying to clarify once and for all lens calculations on 350D and other small sensor cameras.
Lens numbers that are designed for digital are not the 35mm equivelant.
Beacuse the sensor is smaller everything else is smaller too and if its a small sensor lens at 30MM ,to get a lens with the same view on a 35MM camera it will be a 50MM.
I've read this in the lens manuals.

So when someone buys say a sigma lens and it says DC ,it really means you still have to multiply the numbers to picture it against standard lenses.

A sigma 10-20 lens DC equivelant in 35MM format is 17-35.
The reason I'm making such a canoodle about it is because ,I think some people think they are getting more for their money than they actually are.
Also ,canon small lenses won't fit onto standard cameras because of a bit that sticks out ,so be careful when ordering canon EFS lenses ,sigma equivelant fit both types.

If I'm wrong about this please tell me ,I'm almost sure about it .

Brian.

Beano

you pretty much summed it up. Lenses designed for smaller sensors (ef-s for canon and DC for sigma) wont fit on a full-frame camera, digital or film. You always have to multiply the focal length by 1.6 even if the lens is a DC or EF-S.

311

Thanks Beano ,just a quickie about sigma dc's though,
I can stick the sigma DC lenses on 35mm (with vignetting),
the canons have a piece sticking out that hits off the mirror of the 35mm.
Canon EFS wont physically fit standard cameras.

Brian.

Irish Wolf

_Brian_ wrote:

Thanks Beano ,just a quickie about sigma dc's though,
I can stick the sigma DC lenses on 35mm (with vignetting),
the canons have a piece sticking out that hits off the mirror of the 35mm.
Canon EFS wont physically fit standard cameras.

Brian.

Oh Lord... no offense but just go to the Canon website, and you'll find that the EF-S series was design specifically for the lower end Canon SLR digital cameras which have the smaller sensor, and NOT for film SLRs.

Oh... btw... 1.6 is the Canon digital multipier only - afaik Nikon digital multiplier is 1.5 - this is open for correction for our Nikon brethren

IMO the "standard" is never going out, and all manufacturers are aiming their guns at getting a full sensor into their digital cameras - to buy a digital specific lense is false economy.

311

Nice one wolf ,but on any internet site you can buy an EFS lens and it says nothing about it not fitting a standard camera.

It's alright to look at a canon website ,if you know theres something wrong.

Brian.

311

Heres a link to an EFS lens on Komplett ,you'll see there is no mention of it not fitting onto a standard SLR ,all it says is that the lens is designed for digital.
There are full frame digital cameras available you know.
http://www.komplett.ie/k/ki.asp?sku=311527&view=detailed

The sigma lenses do fit on the standard cameras ,Fajitas uses a 10-20 on his 1000f.
http://www.sigma-photo.co.jp/english/lens/digital/10_20_4_56.htm

All I wanted to do is make sure anyone who didn't know ,was aware of it when buying a lens ,someone mighten find out for a couple of years.
Also ,it says nothing on the canon website about those lenses not fitting onto 35mm slr camera's ,but it does say that their extenders can't be used with them ,I didn't know that.

Brian.

eas

Oh... btw... 1.6 is the Canon digital multipier only - afaik Nikon digital multiplier is 1.5 - this is open for correction for our Nikon brethren

that's it - 1.5x on nikon - and the DX lenses (exlusivly designed for digital) AFAIK will fit on all f mount nikon cameras - 35mm or digital, but are pretty much useless for film cameras or full frame DSLRS*

*I think it's worth considering that full frame DSLRs will be affordable to the mases in the next couple of years these "special" small frame digital lenses will have a very short product life.

I won't be buying one in anycase.

antifuse

all manufacturers are aiming their guns at getting a full sensor into their digital cameras

This isn't necessarily true. Nikon doesn't seem to be aiming in that direction yet, and a lot of people are saying that they might not bother. And *some* pros are saying that they *shouldn't* bother, because the smaller sensor is better for most folk (including pros) than full frame. I can't say one way or the other, since I'm no pro.

elven

eas wrote:

the DX lenses (exlusivly designed for digital) AFAIK will fit on all f mount nikon cameras - 35mm or digital, but are pretty much useless for film cameras or full frame DSLRS*

Is it just me or is that phrase contradictory? Or is there some Nikon secret that I don't know?

antifuse wrote:

And *some* pros are saying that they *shouldn't* bother, because the smaller sensor is better for most folk (including pros) than full frame.

Apologies in advance, I'm writing this before doing a bit of reading, but why would the smaller sensor be 'better' for anyone? From a simplistic, logical point of view, surely a bigger sensor means more information going into the image file, and that has to be a good thing doesn't it?

It does seem a bit strange, mind you, to be worrying about making DSLR gear compatible with 35mm kit. Is it because there are so many lenses already in circulation that it's better to make the bodies to fit the glass than the other way around?

I don't think I'll be buying any EF-S lenses anyway.*

*Unless someone has an old 350D kit lens that they want rid of to temporarily replace my sigma 28-80 that gives me the dreaded "ERR 99"

Alun

The Sigma 10-20mm lens is a 10-20mm lens, full stop. The focal length of a lens is an immutable property of the lens itself and contrary to popular belief doesn't change depending on what camera you put it on, or the size of the sensor or film. What does change is the field of view (FOV), which leads to the whole rather misleading "35mm equivalent" stuff. What this means in practice is that if you were to take, say, the same 50mm lens and put it on two cameras, one a 35mm and one a 1.5 crop-factor digital camera, then the FOV you'd get on the 35mm camera would be larger than on the digital. In order to get the same FOV on the digital camera you'd have to put a 75mm lens on it. The crop factor is just a convenient way of visualising the different FOV's of the lenses on two cameras with different sensor/film sizes. The focal length remains the same, i.e. what's printed on the lens body.

The only difference between the digital-only lenses and the 35mm lenses is that the digital lenses can be designed in such a way that they don't need to project an image over as large a surface area as their 35mm cousins, and can therefore be made more compact, cheaper and lighter.

You could, if you wanted, take the Sigma 10-20mm lens and put it on a 35mmm camera, in which case it would behave just like any other 10-20mm zoom designed for a 35mm or full-size sensor camera, except you'd get huge amounts of vignetting and distortion around the edges.

311

hadn't a clue i was going to start any conversation ,I just thought someone might put me straight about the calculations if i was wrong:o
And maybe shed a little light for someone that didn't know.

I've got four standard 35mm lenses ,and 3 small lenses .
None of the standard lenses have a field of view you'll get from a wideangle small sensor lens ,on a 350D.

Personally ,I don't see the point in having an slr camera without a wideangle lens.

Elven I can give you a long term loan of my 18-55 ,I didn't realize you hadn't got one :eek:

Sorry If i came across as been arrogant with the thread.
Brian.

eas

The Sigma 10-20mm lens is a 10-20mm lens, full stop.

good points Alun - well explained.

Is it just me or is that phrase contradictory? Or is there some Nikon secret that I don't know?

elven - I'm not sure what you find contradictory about the statement - maybe Aluns post mode more sense out of mine?

Nikkor DX lenses will fit onto Fmount Nikon film cameras, but would not be pratical for everyday use.

311

Alun wrote:

The Sigma 10-20mm lens is a 10-20mm lens, full stop. The focal length of a lens is an immutable property of the lens itself and contrary to popular belief doesn't change depending on what camera you put it on, or the size of the sensor or film.

What does 10-20 mm mean ?? ,is it the distance of the lens from the sensor/film ??

Alun

_Brian_ wrote:

What does 10-20 mm mean ?? ,is it the distance of the lens from the sensor/film ??

For a very simple single element lens, it's the distance from the lens at which a parallel beam of light would be focussed. Imagine a magnifying glass being held up to the sun to try and burn something. You'd want to place the thing being burnt at exactly the focal length of the lens for maximum burning effect.

For complex multi-element lenses like most modern camera lenses, it's a whole lot more complex than that, and instead, what is usually referred to as the focal length, is really an "effective" focal length. In other words, if you could replace your big expensive multi-element 500mm lens with just one single lens element, it would have to be 500mm, or 0.5m (!) away from your film or sensor's surface.

311

Alun ,that was my problem .
I was using them same rules and applying them to a lens that was made for a smaller plane.
At one stage I was actually comparing in value a 10-20 lens to it's 35mm counterpart.
This is the mistake I was pointing out thats easy to make when buying a lens.
Instead of comparing a 10-20 DC to a 10-20 full frame ,compare it to a 17-35mm for value.

Thanks for clearing the picture in my head ,wasn't sure about the whole measurement thing.

Brian.

masteroftherealm

Alun wrote:

The Sigma 10-20mm lens is a 10-20mm lens, full stop. The focal length of a lens is an immutable property of the lens itself and contrary to popular belief doesn't change depending on what camera you put it on, or the size of the sensor or film. What does change is the field of view (FOV), which leads to the whole rather misleading "35mm equivalent" stuff. What this means in practice is that if you were to take, say, the same 50mm lens and put it on two cameras, one a 35mm and one a 1.5 crop-factor digital camera, then the FOV you'd get on the 35mm camera would be larger than on the digital. In order to get the same FOV on the digital camera you'd have to put a 75mm lens on it. The crop factor is just a convenient way of visualising the different FOV's of the lenses on two cameras with different sensor/film sizes. The focal length remains the same, i.e. what's printed on the lens body.

The only difference between the digital-only lenses and the 35mm lenses is that the digital lenses can be designed in such a way that they don't need to project an image over as large a surface area as their 35mm cousins, and can therefore be made more compact, cheaper and lighter.

You could, if you wanted, take the Sigma 10-20mm lens and put it on a 35mmm camera, in which case it would behave just like any other 10-20mm zoom designed for a 35mm or full-size sensor camera, except you'd get huge amounts of vignetting and distortion around the edges.

Focal Length purist!
Its commonly accepted to related the FOV change on an APS-C size digital sensor the the equivalent 35mm/Full Frame sensor because many people will be coming from a film background.
For example, pro photographer X knows his focal lengths in his head due to working with them for 20years, he looks at subject Y and decides he needs 135mm lens. On film thats grand. Photo will turn out like planned. However he is now shooting digital and his 135mm is no longer gonna take the photo he wants so he steps down to an 80mm which will produce roughly the same pic on his DSLR as his 135mm on his SLR. Hence the obvious direct relation to 35mm focal lengths and the easy way to relate the 2.
No point in making things more complicated then they already are

Alun

_Brian_ wrote:

This is the mistake I was pointing out thats easy to make when buying a lens. Instead of comparing a 10-20 DC to a 10-20 full frame ,compare it to a 17-35mm for value.

Yes, a 10-20mm zoom with a FOV suitable for a 35mm camera would be getting into ultra-wide angle, almost fisheye territory, and wouldn't be cheap I'd imagine, whereas a 17-35mm lens for the same camera would be quite affordable. I had something similar, a Cosina 16-32mm if I recall correctly, for my old Minolta film SLR ... beautiful lens it was, sad to see it go

Alun

masteroftherealm wrote:

Focal Length purist!

Yep, pedantry is one of my worst (or best, depending on your point of view!) traits

I thought it was worth pointing out one more time though, because there still seems to be this mistaken idea that the focal length printed on DC or "digital only" lenses is somehow different to that printed on 35mm lenses, and that because they're "digital only" lenses that it has the crop factor somehow "built-in", which definitely isn't the case.

masteroftherealm

Alun wrote:

Yep, pedantry is one of my worst (or best, depending on your point of view!) traits

I thought it was worth pointing out one more time though, because there still seems to be this mistaken idea that the focal length printed on DC or "digital only" lenses is somehow different to that printed on 35mm lenses, and that because they're "digital only" lenses that it has the crop factor somehow "built-in", which definitely isn't the case.

Yeah actually very good point. I wondered that myself the first time I saw the Digital Only ones.

And to the dude above bout wether APS-C sensors are here to stay methinks so. Not brilliant for myself as wide angles are harder to get now! But lovely for wildlife shooters, whos 500 f/4 L (Drool) has now become an even more useful 800mm f/4 L Equivalent Lens

antifuse

If anybody cares, here's Ken Rockwell's page on sensor sizes (he was the pro that I remembered talking about why it's not necessary to go full frame) - here's a snippit:

Today the current 16 x 24 mm size sensors are ideal and have many advantages over the dinosaur size of 35mm still film. Among these are deeper depth of field leading to sharper pictures since the focal lengths are shorter, and smaller, lighter and less expensive lenses since everything can just be smaller.

antifuse

elven wrote:

Is it just me or is that phrase contradictory? Or is there some Nikon secret that I don't know?

It's not contradictory. You can mount Nikon digital (DX) lenses on 35mm or digital SLRs, but they aren't that useful when mounted on a 35mm camera because you get huge vignetting problems (due to it being designed for the smaller FOV of the smaller digital sensor)

311

Lads ,was thinking about what the guy said about small sensor cameras.
And would I be right in saying ,it's the glass that counts when taking photos.
can't see a great picture coming from a pinhead of glass ,unless they develop some super duper fractal glass thingy that can pull an image in from the tiniest of masses :eek:

elven

antifuse wrote:

It's not contradictory. You can mount Nikon digital (DX) lenses on 35mm or digital SLRs, but they aren't that useful when mounted on a 35mm camera because you get huge vignetting problems (due to it being designed for the smaller FOV of the smaller digital sensor)

Aaaaaah... so it will physically fit, but because of the vignetting, it's not of much use.

Just a misunderstanding of the phrase then.

311

Elven I can give you a loan of my 18-55 ,I say loan because on the off chance I might need it if I sell my camera or something ,which isn't going to happen for at least a couple of years .

It's there if you want it

Brian.

masteroftherealm

_Brian_ wrote:

Lads ,was thinking about what the guy said about small sensor cameras.
And would I be right in saying ,it's the glass that counts when taking photos.
can't see a great picture coming from a pinhead of glass ,unless they develop some super duper fractal glass thingy that can pull an image in from the tiniest of masses :eek:

Yup good glass should be No1 on a photogrpahers gear list. I know peeps with 10k worth on canon L glass on a 300d and have amzing photos!

eas

elven wrote:

Aaaaaah... so it will physically fit, but because of the vignetting, it's not of much use.

Just a misunderstanding of the phrase then.

my partial grasp of the englsih language probably had something to do with it as well

elven

_Brian_ wrote:

Elven I can give you a loan of my 18-55 ,I say loan because on the off chance I might need it if I sell my camera or something ,which isn't going to happen for at least a couple of years .

It's there if you want it

Brian.

Cheers, I might take you up on it - as long as you don't use it yourself - I sometimes can't shoot at maximum aperture so my sigma zoom is mince.

If I make use of it for a couple weeks I'd prolly go buy one, or an equivalent, just not a sigma

311

elven wrote:

Cheers, I might take you up on it - as long as you don't use it yourself - I sometimes can't shoot at maximum aperture so my sigma zoom is mince.

If I make use of it for a couple weeks I'd prolly go buy one, or an equivalent, just not a sigma

I never use it ,it's ok as a lense but I am a bit heavy handed so it didn't suit me.

Give me a shout ,I'd rather someone got some use of it.

Brian.

andy1249

Love these threads , they just keep coming up ,

For the record , I'm one of the older posters here and am coming from ye old world of film to the new world of digital , I have a 20D , and love it , I also have a collection of lenses , My current favourite film camera is a Canon 300x , all my gear is Canon ,

One thing I would love to point out , the only EF-S lens I have is the kit lens , that fairly average 18-55 that came with the 20D , this will not fit any of my canon film camera EF Mounts , the lens physically touches the mirror and will scratch it if forced on !!
I believe from all the reading up that Ive done , that this is unique to Canon !

Now My Brother tells me that with Nikon Digital lenses that is not the case , and also the sigma digital lenses apparently fit on both mounts as well.

So for this reason , my Ultrawide , which I hope to get soon , is gonna be a Sigma or Tamron and not a canon , as I want it to mount on both the film and Digital Canon cameras that I have.

311

Andy ,I used the 30MM DC lense on my canon 50E and it worked great.
The thing was ,when i got the films developed there was no vignetting in the photos.
The view is about a 20mm when it's on the 35mil.:)

Brian.

andy1249

Brian , is that a Sigma 30mm that you are talking about there ,
And just to be clear , how are you calculating that it was 20mm on a 35mm camera ?

311

It looked about 20 - 24 ,thats all i can say .
It was a lot wider view on the 35mm ,took a few shots in a dark pub and the skin tone came out lovely.

The lens is the 30mm 1.4dc
Brian

JMcL

antifuse wrote:

If anybody cares, here's Ken Rockwell's page on sensor sizes (he was the pro that I remembered talking about why it's not necessary to go full frame) - here's a snippit:

Bob Atkins has some good points here. The greatest advantage offered by APS-C sensors is the effect the mutliplier gives at the telephoto end. One of the key points he make is that the the longest lens Canon makes is 600mm, if you add a 1.4x TC this'll bring you up to 840mm with a slight reduction in image quality. On a 20/30D you're up to 960mm equivalent FOV the moment you put it onto the camera, or over 1300mm with a 1.4x TC! Why would anybody want a focal length like this? As far as professional bird photographers are concerned, there's no such thing as too long a focal length.

Directly related is the notion of cost. The 600mm lens above comes in to a cool €8000 odd from AC-Foto, it's also enormous. In a more real world situation, a decent 300mm lens is transformed into a very useful 480mm equivalent, for an awful lot less than the cost of a 500mm lens to put onto a 5D.

There are advantages to bigger sensors. The wide end, the ability to pack more pixels on at a lower density, which leads to lower noise, also, and contrary to the Ken Rockwell quote, shallower depth of field ahould you want it.

From a production perspective, smaller sensors will always be cheaper to manufacture, as there's a much lower rejection rate than larger pieces of silicone. The gap may narrow, and given the price of the 5D, actually has narrowed, but I'm not sure by how much.

I personally like having the option of the longer telephoto end, and given that there're good lenses like the Sigma 10-20 to cover the wide end, at the moment I'm leaning towards upgrading to whatever the real replacement for the 20D turns out to be, though of course I retain the right to completely change my mind on this

John

masteroftherealm

For huge focal length lenses. Try a sigmonster 300-800mm sigma, with a two 1.4 TCs and two 2x TCs on an APSC body
Used for moon photogrpahy ;p (over 12000mm focal lengt equiv)

311

masteroftherealm wrote:

For huge focal length lenses. Try a sigmonster 300-800mm sigma, with a two 1.4 TCs and two 2x TCs on an APSC body
Used for moon photogrpahy ;p (over 12000mm focal lengt equiv)

Any chance of catching a shooting star with that

JMcL

masteroftherealm wrote:

For huge focal length lenses. Try a sigmonster 300-800mm sigma, with a two 1.4 TCs and two 2x TCs on an APSC body
Used for moon photogrpahy ;p (over 12000mm focal lengt equiv)

And the world's heaviest tripod to go with it i guess!

masteroftherealm

Yup u could say that!!!

mervifwdc

Actually, Canon have kindly given us a few factors for their cameras. 300,350,20 and 30's are all 1.6 factors, while the 1 series (except the 1ds series) are 1.3 factors.
unless of course you have the 5d, or 1ds which is full 35mm, or 1 factor.

Merv.

melekalikimaka

JMcL wrote:

And the world's heaviest tripod to go with it i guess!

just get one of those thingys they use to move cannons on ships

CalebHawke

Sigma also do a few lenses that are only designed for the smaller sensors. I bought the 10-20mm Sigma and although it will fit on a film camera or full 35mm digital camera like the 5d it will produce vignetting at the wide end so pretty much becomes useless on these cameras.