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Why no fast zooms/telephoto for APS-C sensors?
I have been looking at the Olympus system (as well as others) very closely..

And what I have noticed is that nearly all of their top end zooms and telephoto lenses are fast f2.0 or f2.8 lenses. And I understand that by the end of this year, all of their telephotos will be available as f2.0..

Another thing I notice is that they, by and large, produce these lenses as constant aperture lenses..

Now I understand that the reason Olympus are able to do this easily is because their sensor is much smaller than full frame 35mm..

Well, that's where I begin to scratch my head. Why?.

Well, the APS-C sensor is also much smaller than a full frame sensor. Yet whenever I see lenses specifically designed for the reduced circle of APS-C, they are by and large very slow lenses and hardly ever offer constant apertures..

Why is this?.

Do Olympus have some kind of patent or technique that no-one else has? Or what?.

Thanks in advance...

Comments (15)

The smaller sensor of the Oly system compared to the APS-C cameras means that they need shorter focal lengths to get the same field of view in the image. So a 50-200 zoom on my Pentax (for example) is approximately matched by the Olympus 40-140, give or take. Likewise a 'standard' 18-55 kit lens on Pentax / Canon / Nikon is about equivalent to the Olympus 14-42mm..

With shorter focal lengths it is easier to get wider f-stops without making the lens too big and bulky. The designation 'f/4' does not mean a fixed size hole, but is actually a ratio of the front lens element (approximately) to the size of the aperture. A 100mm focal length lens with a 25mm hole in it is f/4: a 50mm focal length lens with a 25 mm hole in it is f/2 (the fact that the shorter focal length of the lens concentrates mroe light over a smaller area results in a higher effective exposure, by two stops in this case)..

So: shorter focal length lenses, which are needed with smaller sensors, are easier to make with wider f-numbers as you don't need so much glass and plastic. If you have an 80mm lens and want it to be f/2, you need a 40mm aperture in it. For a 60mm lens at f/2, you only need a 30mm aperture in it, so it's easier and chaper to make..

Best wishesMike..

Comment #1

Mike703 wrote:.

The smaller sensor of the Oly system compared to the APS-C camerasmeans that they need shorter focal lengths to get the same field ofview in the image. So a 50-200 zoom on my Pentax (for example) isapproximately matched by the Olympus 40-140, give or take. Likewisea 'standard' 18-55 kit lens on Pentax / Canon / Nikon is aboutequivalent to the Olympus 14-42mm..

With shorter focal lengths it is easier to get wider f-stops withoutmaking the lens too big and bulky. The designation 'f/4' does notmean a fixed size hole, but is actually a ratio of the front lenselement (approximately) to the size of the aperture. A 100mm focallength lens with a 25mm hole in it is f/4: a 50mm focal length lenswith a 25 mm hole in it is f/2 (the fact that the shorter focallength of the lens concentrates mroe light over a smaller arearesults in a higher effective exposure, by two stops in this case)..

So: shorter focal length lenses, which are needed with smallersensors, are easier to make with wider f-numbers as you don't need somuch glass and plastic. If you have an 80mm lens and want it to bef/2, you need a 40mm aperture in it. For a 60mm lens at f/2, youonly need a 30mm aperture in it, so it's easier and chaper to make..

Best wishesMike.

Thanks for that reply..

I understand what you say..

However, there is a weakness in the argument you put forward. It is this: a very popular zoom is the 70-200mm f2.8. Now this lens, with the exception of the Olympus 4/3rds equivalent, is always (as far as I know) made to cover the image circle of a full frame sensor. Well, if the full frame sensor is so much bigger than an APS-C sensor, why aren't there any faster 70-200mm f2.0 lenses for the exclusive use on the reduced circle of the APS-C sized sensor? Surely if a lens can be made as fast as f2.8 for full frame, would it not be easier to make that lens, and make it faster, for the APS-C sensor?.

Sigma for example have just announced a monster 200-500mm f2.8 constant aperture lens (wieghing in at 16kg, if my memory serves me correctly). Why did they, or any other company, not make a similar lens for the APS-C format? Would it not have been much smaller and lighter?.

Thanks in advance...

Comment #2

I see what you mean..

Just guessing... wide-aperture tele zooms are expensive. Maybe the manufacturers figure that there is a high chance that anyone buying these lenses is more likely to have a 1Ds MkIII or Nikon D3, the full-frame pro-level cameras. Someone paying 3000 for a body is not going to stick a 150 70-300 f/4-f/5.6 zoom on it; but there is a good chance that someone paying over 1000 for a 70-200 f/2.8 will have a full-frame camera. So these fast lenses are made mostly for the pro market (which means Nikon and Canon only, more or less) and need to have full frame coverage, but enthusiasts with APS-C cameras can also use them..

This may be rubbish of course but it seems plausible....

Best wishesMike..

Comment #3

Hmm, I was thinking along similar lines..

However, it doesn't explain Pentax and Sigma who don't make full frame cameras...

Comment #4

Plevyadophy wrote:.

I have been looking at the Olympus system (as well as others) veryclosely..

And what I have noticed is that nearly all of their top end zooms andtelephoto lenses are fast f2.0 or f2.8 lenses. And I understand thatby the end of this year, all of their telephotos will be available asf2.0..

You understand incorrectly. The only f/2 lenses Olympus planned were the 14-35mm and 35-100mm. The 35-100mm is available. The 14-35mm was first announced 3 years ago, it has yet to become available..

All the other major systems have constant aperture f/2.8 zoom lenses covering the range from 16 or 17mm up to 200mm, some even up to 500mm if you include third party makers..

Well, the APS-C sensor is also much smaller than a full frame sensor.Yet whenever I see lenses specifically designed for the reducedcircle of APS-C, they are by and large very slow lenses and hardlyever offer constant apertures..

You can say the same thing of olympus. They have only two fast constant aperture zooms, supposedly with a third to be added this year. Most of their zooms lenses are variable max aperture..

Why is this?.

Cost. Have you seen the price of the Olympus 35-100/2? Canon 70-200/2.8 IS? Sigma 200-500/2.8?.

Do Olympus have some kind of patent or technique that no-one elsehas?.

No, Olympus doesn't have a patent on marketing vaporware..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #5

Plevyadophy wrote:.

This: a very popular zoom is the 70-200mm f2.8. Now this lens, withthe exception of the Olympus 4/3rds equivalent, is always (as far asI know) made to cover the image circle of a full frame sensor. Well,if the full frame sensor is so much bigger than an APS-C sensor, whyaren't there any faster 70-200mm f2.0 lenses for the exclusive use onthe reduced circle of the APS-C sized sensor?.

The "olympus equivalent" to a 35mm format 70-200mm f/2.8 zoom is 35-100mm f/1.4. The APS-C equivalent is 45-135mm f/1.8. So it seems that neither format has the true equivalent..

There are APS-C 50-135mm f/2.8 (Pentax) and 50-150mm f/2.8 (Sigma, for Sigma, Canon and Nikon)..

Surely if a lens can bemade as fast as f2.8 for full frame, would it not be easier to makethat lens, and make it faster, for the APS-C sensor?.

Sure. If you want to go by the same aperture "equivalency" Olympus uses, it would be f/2.5 for APS-C..

Sigma for example have just announced a monster 200-500mm f2.8constant aperture lens (wieghing in at 16kg, if my memory serves mecorrectly). Why did they, or any other company, not make a similarlens for the APS-C format? Would it not have been much smaller andlighter?.

No, it would be the same size and weight. You could enlarge the internal baffles (which would weight a tiny bit more) and make the rearmost element or two a bit smaller (which would weigh a tiny bit less)..

There is no weight savings in going to a smaller format at the same focal length and aperture..

Thanks in advance..

You're welcome..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #6

Plevyadophy wrote:.

However, it doesn't explain Pentax and Sigma who don't make fullframe cameras..

Sigma made "full frame" cameras. The Kodak SLR/C was a Sigma body with Canon mount. They haven't jumped in with their own mount..

Pentax made a 35mm DSLR but abandoned it before it was launched. They may do one in the future, or maybe not. They may even do a 645 DSLR..

Sony hasn't yet made a 35mm DSLR, but they've announced it and I believe they will do it, but maybe not by the end of the year. Pre-announcements are usually made to hold off customers that may jump ship, so dates are often optimistic..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #7

Nickleback wrote:.

Plevyadophy wrote:.

I have been looking at the Olympus system (as well as others) veryclosely..

And what I have noticed is that nearly all of their top end zooms andtelephoto lenses are fast f2.0 or f2.8 lenses. And I understand thatby the end of this year, all of their telephotos will be available asf2.0..

You understand incorrectly. The only f/2 lenses Olympus planned werethe 14-35mm and 35-100mm. The 35-100mm is available. The 14-35mmwas first announced 3 years ago, it has yet to become available..

All the other major systems have constant aperture f/2.8 zoom lensescovering the range from 16 or 17mm up to 200mm, some even up to 500mmif you include third party makers..

Well, the APS-C sensor is also much smaller than a full frame sensor.Yet whenever I see lenses specifically designed for the reducedcircle of APS-C, they are by and large very slow lenses and hardlyever offer constant apertures..

You can say the same thing of olympus. They have only two fastconstant aperture zooms, supposedly with a third to be added thisyear. Most of their zooms lenses are variable max aperture..

Why is this?.

Cost. Have you seen the price of the Olympus 35-100/2? Canon70-200/2.8 IS? Sigma 200-500/2.8?.

Do Olympus have some kind of patent or technique that no-one elsehas?.

No, Olympus doesn't have a patent on marketing vaporware..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed.

I have just checked. Olympus have 4 constant aperture zooms. They have 6 lenses at f2.0 or f2.8. And this does not include recently announced lenses..

As for the 14-35mm, it is in fact available now..

By and large their lenses to to be faster, even the variable aperture ones, which go to around f3.5..

Your argument re expense is a sound one, except for the fact that I wonder why Olympus don't seem to think it is a problem and go ahead and make these fast expensive lenses, whilst Canon and Nikon with a far larger customer base don't seem to bother...

Comment #8

Plevyadophy wrote:.

Hmm, I was thinking along similar lines..

However, it doesn't explain Pentax and Sigma who don't make fullframe cameras..

I think it comes down to cost versus likely market size plus bulk of the end product lens..

Olympus having invented the 4/3rds format are designing for that market exclusively. With the smaller sensor goes a noise penalty so they also need f/2 more than APS-C sensor cameras..

All other mfrs have a 35mm/full frame market to bear in mind. Sigma do not make lenses exclusively for the DP-14. They make a lens with different mounts to fit many cameras. So they must try to maximise their market by covering both full frame and APS-C wherever possible. Wherever they are making APS-C only they are likely competeing with full-frame competition from the mfr and thus are likely building down to a price..

You also need to look at cost of the end product. A Zuiko 35-100 f/2 retails for about 1600 in the UK. A Sigma APS-C 50-150 f/2.8 covering almost exactly the same focal length costs around 430. Get the picture? At those sort of prices Nikon & Canon are building full-frame lenses like the Nikon 24-70 f/2.8 (Indeed the cost of that is significantly less than the Olympus).

Chris Elliott.

*Nikon* D Eighty + Fifty - Other equipment in Profile.

Http://PlacidoD.Zenfolio.com/..

Comment #9

Plevyadophy wrote:.

I have just checked. Olympus have 4 constant aperture zooms..

I said fast constant aperture zooms. But even if you count all constant aperture zooms I get 3: 7-14/4, 35-100/2, 90-250/2.8..

Want to count Nikon or Canons?.

What's the point?.

They have 6 lenses at f2.0 or f2.8..

Zooms or primes? And if zooms, are they constant aperture? No..

As for the 14-35mm, it is in fact available now..

Link to a place selling it right now?.

By and large their lenses to to be faster, even the variable apertureones, which go to around f3.5..

They are on a smaller format..

Your argument re expense is a sound one, except for the fact that Iwonder why Olympus don't seem to think it is a problem and go aheadand make these fast expensive lenses, whilst Canon and Nikon with afar larger customer base don't seem to bother..

Canon and Nikono have plenty of lenses. It would be nice if they made a fast 50-150mm, but Sigma covers that well..

And Canon and Nikon has 35mm cameras and all the fast glass to fit it if you like..

Both Canon and Nikon have APS-C 17-55mm f/2.8 lenses. These have been available for at least two years. They are half the expected price of the 14-35/2.0..

BTW, I'm not slagging Olympus. They make nice stuff. If you want an Olympus camera and 14-35/2 lens, go ahead and buy them. But wait a bit, because the 14-35 isn't out yet..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #10

Plevyadophy wrote:.

However, there is a weakness in the argument you put forward. It isthis: a very popular zoom is the 70-200mm f2.8. Now this lens, withthe exception of the Olympus 4/3rds equivalent, is always (as far asI know) made to cover the image circle of a full frame sensor. Well,if the full frame sensor is so much bigger than an APS-C sensor, whyaren't there any faster 70-200mm f2.0 lenses for the exclusive use onthe reduced circle of the APS-C sized sensor? Surely if a lens can bemade as fast as f2.8 for full frame, would it not be easier to makethat lens, and make it faster, for the APS-C sensor?.

Nikon has a 200mm f/2 VR lens. It's $4000. That's why you don't see a lot of long f/2 lenses. It would only be slightly smaller if it was limited to APS-C..

The 135mm f/2 is sort-of equivalent on an APS-C body and it's "only" $1000, without VR, but with DC (defocus control)..

Now that both Canon and Nikon have full-frame bodies, I think you'll see little interest in exotic crop-sensor lenses, except a couple wide-angles...

Comment #11

Camera makers are driven by a combination of research, marketing and production considerations..

First of all, can they invent some lens. They may have invented lots of lenses we don't know about, because....

Second of all, would people buy this lens. Maybe it serves some great photographic purpose, but....

Third of all, can they make the lens, for a price that matches the prioce and demand curve determined by the marketing considerations..

Meeting your requirement is the 50-150mm f2.8 Sigma, giving APS-C owners the field of view, and maximum aperture, loved by fewer-than-you-may think owners of 70-200mm f2.8 lenses used on 35mm film cameras..

I think there's one superwide zoom that's wider than any full frame wide angle zoom priced anywhere near it, and witha fixed maximum aperture. Plus lots of variable aperture super wide angles for less money than anything comparable for a 35mm film or so-called full frame D-SLR. I'n not up to speed on Pentax APS-C only lenses..

As for other fixed aperture zooms if I was at Canon's marketing department, I'd want the research money and the marketing money devoted to the 24-70 f2.8, for instance, spread over 1.6, 1.3 and full sensors..

BAK..

Comment #12

Plevyadophy wrote:.

Your argument re expense is a sound one, except for the fact that Iwonder why Olympus don't seem to think it is a problem and go aheadand make these fast expensive lenses, whilst Canon and Nikon with afar larger customer base don't seem to bother..

Canon just came out with a 200mm F2 - it's estimated price is $6000. Can you imagine how much a 70-200 F2 would cost?.

No matter what size sensor, anything at 200mm F2 requires a 100mm wide entrance pupil. They are extremely expensive. I don't believe Canon makes anything with that large of an entrance pupil for less than $5000..

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Comment #13

IMac, therefore iAm wrote:.

No matter what size sensor, anything at 200mm F2 requires a 100mmwide entrance pupil. They are extremely expensive. I don't believeCanon makes anything with that large of an entrance pupil for lessthan $5000..

300mm f/2.8, which has a 106mm entrance pupil, $3900:.

Http://www.bhphotovideo.com/.../Canon_2531A002_Telephoto_EF_300mm_f_2_8L.html.

Of course the Olympus 300/2.8 is quite a bit more expensive and heavier..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #14

Nickleback wrote:.

IMac, therefore iAm wrote:.

No matter what size sensor, anything at 200mm F2 requires a 100mmwide entrance pupil. They are extremely expensive. I don't believeCanon makes anything with that large of an entrance pupil for lessthan $5000..

300mm f/2.8, which has a 106mm entrance pupil, $3900:.

Http://www.bhphotovideo.com/.../Canon_2531A002_Telephoto_EF_300mm_f_2_8L.html.

Good catch - forgot about that one!..

Comment #15

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