EF-S and 3rd party DC glass question.

[derrickdehaan]

Am I mistaken when in my understanding, EF-S and 3rd party glass like Sigma's DC of lenses act just as they

should on a crop sensor? Meaning for example....I have a Sigma 17-70mm DC lens. Some people are telling me

that it acts like a 27mm-112mm when compaired to a full frame lens? I thought that the EF-S and/or DC designation

meant it was made for crop sensor cameras therefore the field of view would be true to the focal length. I know at

17mm the lens looks pretty darn wide on my 40D. I thought that the "multiply by 1.6 rule" only applied if using EF

glass on a crop body. Thanks folks.

 

Derrick

[bobatkins]

Field of view depends on focal length AND format size.

 

Focal length alone does NOT define the field of view.

 

You multiply the focal length of a lens on an APS-C cropped sensor camera by 1.6x, to get the focal length of the lens that will give you the same field of view on a full frame camera.

 

17mm on a 40D = 28mm on a 5D

 

If you want the full technical details, see http://www.bobatkins.com/photography/technical/field_of_view.html

[derrickdehaan]

Thanks Bob, that sheds more light on what I needed to know. So my next question would then be- why EF-S glass exsists? Why not just a 10-20 EF mount? Perhaps its because of lens design limitations?

 

Derrick

[tommyinca]

Why not just a 10-20 EF mount?

 

It could, but Canon decided not to. Here are two reasons.

 

1. EF-S lens' rear element can be closer to the sensor becuase of smaller mirror in 1.6X crop sensor body. This, in

theory, can have design advantage for wide angle lens. (More details you need to know: less agrressive retro focus

elements are needed)

 

2. Because of #1. It is nessesary to have a EF-S lens mount so folks can not mount a EF-S lens on an EF body and

ther by

damage the expensive to replace mirror.

[bobatkins]

I think the EF-S lens mount was an error on Canon's part. I don't think the possible potential small gain in optical quality for very wideangle lenses is worth the incompatibility with FF bodies. Nikon and the 3rd party lens makers didn't bother with an incompatible mount and they seem to do just fine.

 

Yes, crop sensor lenses vignette badly on FF bodies, especially at the wide end of zooms, but so what. Doesn't bother Nikon users or 3rd party lens users. Zooms at their long end can give acceptable FF images.

 

I think the EF-S lens mount was likely an idea that came out of the technical department, but it would have been better if they'd run it through marketing and customer relations before putting it into production. I think its disadvantages outweigh any potential slight advantages.

[JDMvW]

Theory-

 

EF-S lenses would be cheaper to build because of not needing to cover so large an area (have you ever been

jealous of those f/0.8 lenses that cover only 8mm film or some such?)

 

EF-S lenses could theoretically be easier to design in ultra wide angle if it didn't have to clear so large a

mirror in an SLR. (The first Nikkor fish-eye required the mirror to be folded up to use the lens, and the

difficulty in getting wide angle lenses for the early SLRs was only solved with retrofocal designs like Angenieux's)

 

Practice-

 

With the possible exceptions of the EF-S kit lenses, any cheaper cost in manufacture does not seem to much affect

consumer prices.

 

It is not clear that the 10mm focal length lenses do have much problem with FF mirrors. The Sigma 10-20mm seems

to mount (with vignetting of course) reasonably well on the Canon 5D, for example. I am obliged to note,

however, that I did get a mirror/lens collision on one of my EOS film bodies, the EOS 700 I think. Fortunately

after I got them apart, a reboot seemed to restore normal function, but it is an experiment I will not be repeating.

 

In short, like some other forays into innovation that Canon has undertaken (e.g., eye-control of focus,

diffraction optics) I think that this will be allowed to fade out as time passes.

 

Please, enthusiasts for the EOS 5 (of which I have one) and for the diffraction lenses like the 70-300mm, don't

write. I did not say these were not worthwhile, merely that they were not evolutionarily successful insofar as

they do not seem to have founded new "families" of products.

[petemillis]

I reckon (conspiracy theory here) that Canon know the crop sensor bodies are more likely to be bought by amateur,

who then become enthusiasts and but a whole stash of EF-S lenses to fit. And as they become more enthusiastic

they listen to everyone who tells them they need a full frame body so they go out and buy a 5D. Now of course they

need to go and buy another stash of EF lenses.

[freelance]

I hope that this important statement coming from an authority as Bob Atkins will finish the controversial about the inconvenience of purchasing expensive EF-S lenses. Even before thinking of buying a full frame, the part of common sense that I try to apply to everything in life made me reject something that you could only use in a specific sector of EOS cameras. Cameras with smaller sensors to make them cheaper. It is true that this cameras are excellent for telephotos, but this is accidental. The forecast is that the development of photography will make the FF the most used format in the future in DRLS.

[freelance]

Think: Would anybody buy a 500 mm EF-S? Why a macro (EF-S 60) that you may use even less? or a wide angle (10-22) that it is actually a 16 and will be useless when you can buy a 5D for 500 bucks? When I saw I needed, not wishing, a wide angle, I bought a 5D and wide angle EF lenses.

 

Before digital era came, would any photographer have bought a "crop film camera" with "crop film lenses"? I think we have are being manipulated and in a couple of years thousands of people are going to rush to eBay to sell EF-S lenses almost for nothing.

[freelance]

I only understand EF-S purchases for short term intense activity.

[freelance]

Sorry, controversy not controversial

[freelance]

Continuing with the “forecasting”, knowing a little bit of marketing and even less of photography, I would say that it is highly improbable that a 50D should be developed. I think that the 40D will be the last of the “deca D” saga and Canon will continue the consumers DLSR through Rebel models. FF sensors will be more available and people will tend to buy this type of cameras for professional and semiprofessional use. I said people will try to sell expensive FS-S lenses buy will keep the crop factor cameras for telephotos.

 

I miss nevertheless a “point and shoot” pocket camera for professional use different than photography. It should be small, light (to put in my shirt or jacket), much wider that now (at least real 17), high iso (3200 if possible), not more that 5 megapixels but good pixels, built in flash just in case, good macro functions and 3x or even 5X optical zoom, NO DIGITAL ZOOM AT ALL. I would try to get quality without having to use RAW. Too time consuming for non professionals. And video functions.

 

I would not mind to pay 1200 $ or more for this as I could use it for building, documents, meetings, machinery, events, exhibitions, samples, etc.

It is not only my opinion but the questions I have been receiving from a lot of architects, lawyers, economists, politicians, sellers, and buyers, etc. I offer this information to Canon for free.

[JDMvW]

Antonio - I think the camera you want is available now. It's called a "Leica". Of course it costs a little more

than $1200.

 

If Bob is to be accepted as a prophet, then you need to pay attention to his earlier prophecy about the "economy

of scale" (smaller sensors will always be cheaper to produce than larger ones, so....) I think it's somewhere on

his site at http://www.bobatkins.com/photography/index.html , but I'm hoping he will hop in at some point here.

 

For myself, this argument about the "superiority" of full-frame only makes sense for those of us who grew up with

35mm film. The so-called "crop body" is nothing of the kind; it's simply a different format like half frame, or

6x6 cm.

 

It's not the size of the sensor that matters so much as it is the quality of the image. It's certainly probable

that larger sensors will always have some kind of edge, just as a 4.5x4.5 cm sensor would have an edge over

36x24mm, but even now, the practical results and differences between a FF and "crop" body are largely irrelevant

until you make huge prints. I don't expect that medium-format sensors, cheap as they may become at some future

date, will automatically swamp out either smaller format. Just so, 6x6 film never replaced 35mm film, superior

though it might have been in picture quality. And what ever happened to spocketed 70mm film? -- it seemed like

such a good idea.

[freelance]

I did not say that Bob was a prophet, but that he has made an important statement. He considers TODAY that the EF-S mount was an error. I feel this long ago. I was the one who dared to do "prophecies". A few days ago a read in photo.net that somebody was waiting for the 50D. What for? What more functions can Canon add to a DLRS that is supposed to be purchased from today onwards by amateurs and semiprofessionals. If future 5D gets the same speed that the 40D, a crop factor will be needed only for telephotos in the professional field. This was my forecast.

 

 

I think that Canon should attend a new and very wide segment of professional that are emerging. A lot of people that use the photography in their works and cannot hang a lot of gear all day or go to meetings or lunches with a Lowepro. This professionals need good pictures (very wide angle, low light to avoid flashes in many occasions, IS, video, a zoom to reach at least 80mm or more), etc, all in a ultra compact format. They are need of good IQ but not many pixels (We already know and avoid the pixels war). Pictures that fills the hard drive of hundreds of Gigas (I had to buy a HD of 1 Tera because of the pictures). Andall these proffesionals have money to afford this inexistent camera. It could be named “compact for project managers” . I also give Canon a new gift.

[freelance]

Sorry, JDM, this first part was lost:

 

Thanks, JDM, for the information. As you don’t say the model of Leica I suppose you refer to M8, a DLRS of 4500 $ that is not the tiny camera I dream (It weights 19,2 oz or 545 gr. The compact Leica D-LUX 3 ($600) is a 28 mm, not a 17 or 18. The Leica V-Lux 1 (about 800 $) is 23,6 oz and 35 mm. Both compacts lacks many of “my specifications” too.

[kasperhettinga]

I agree with the last post. Only thing is that the bigger film in those days also came with bigger/heavier bodies and more expensive processing: this didn't help either in getting a wide use.

A full frame-sensor will even fit a small and light-weight body. And processing costs are no longer relevant. This may make full frame sensors find a wider use in DSLR.

 

However, I still agree that economy of scale will keep the crop sensor in use. So I wouldn't worry too much about the price of used EF-S lenses plummeting too much. Although I can image that if only the Rebel-DSLR would keep on using crop sensor in the future, the more expensive EF-S lenses may loose some more money...

[bjscharp]

There's one `EF-S' lens I have that I consider useful: the Sigma 30mm 1.4

It's what my 50mm is on my EOS 30: There for when I don't need anything else.

 

There is no equivalent FF-lens, (not counting the EF 35mm 1.4, which is simply too expensive for a `standard prime', and too big and heavy as well). It'll go with the camera if I ever go FF digital, until then, I love it.

 

But it is indeed the only APS-C lens I've got, aside from the kit-lens I have lying around somewhere (anyone interested?)

[yakim_peled1]

>> I only understand EF-S purchases for short term intense activity.

 

I agree with you but as I have no clue how short will that term be I traded two* of my L lenses (17-40/4, 24-105/4) for two EF-S lenses (10-22, 17-55/2.8) about a year ago and I am very happy with my decision. I am shooting NOW and I am very happy NOW. If and when my preferences change I will simply sell them. I did that many times before and I see no problem with this methodology. I always match my current kit to my current needs and I am never seems to be able to know when will my needs change and to which direction will they stir. Hence I always concentrate on the present.

 

* It will soon be three as my 35/1.4 is collecting dust since getting the 17-55/2.8 IS. I will thus sell it shortly.

 

Happy shooting,

Yakim.