Crop sensors need cropped lenes

[Skulker]

I used to have a 7D. A camera I took many pictures with and really enjoyed. But I was using it mainly behind L series lenses because I wanted the quality that those lenses provide. This has proved to be a good investment as I now have a 5D3 and a 1Dx and the lenses work with them.

I don't want more megapixels, I've got more than I uses almost always. And before anyone suggests it I certainly don't want more just so I can crop them away.

One of my main problems with all this kit is the weight, carrying 40Kg on a trek to a wild life photo opertunity can be a pain.

When the 7D2 comes out the thing that would get me to buy one would be if light weight lens were available with similar quality to the L series but making use of the reduced diameter needed for the smaller sensor. (While they are at it they can reduce the price as the elements aren't as big. )

I know its not going to happen but it would be nice if it did. ------- Just think a nice quality 200-400 with built in 1.4x at about 1/2 the weight and cost in front of a crop sensor giving equivalent view to a 300 to 900 on a FF. 8)

( BTW There can be little doubt that someone who thinks they know better will ridicule this idea. If they convince me that they are right I will claim I was being sarcastic ;D )

 

[wsmith96]

I would think that there is a market for what you are describing, but I suspect the camera manufacturers are not inclined to do this as it could cost them sales on full frame equivalents. This is where what Sigma is doing with their new lens lines is so interesting to me. They are bringing high lens quality down to the price points that mainstream customers, like myself, are willing to pay, and they appear to be targeting the consumer market.

my .$02

 

[Drizzt321]

I would think that there is a market for what you are describing, but I suspect the camera manufacturers are not inclined to do this as it could cost them sales on full frame equivalents. This is where what Sigma is doing with their new lens lines is so interesting to me. They are bringing high lens quality down to the price points that mainstream customers, like myself, are willing to pay, and they appear to be targeting the consumer market.

my .$02

Partially agree, I think the problem is that the 1st party (Canon/Nikon/etc) view the crop bodies as consumer oriented, and so people won't spend $1+K on a lens when they can be one that looks similar for $300. Consumer mentality. So they figure target the audience who will buy such expensive lenses, which is invariably the "pro" market which is generally FF/1D body people. With the 7D2, if it's basically a crop/mini 1DX with associated capabilities, I see that there definitely would be a pretty decent market for a very high quality/durability super-wide zoom and normal zoom (24-70 equivalent). Otherwise, once you get much beyond those 2 areas, you might as well keep your lens lineup consolidated because people are buying the telephoto/super-telephoto for the reach, and the crop will give you narrower FoV which extends the apparent focal length of those lenses. Besides, even if you make a 500mm for a crop, it's still going to be pretty big and heavy and you'll want a tripod anyway. Much cheaper and easier to not split the product lines like that.

 

[schill]

Would a 300/2.8 (or anything else for that matter) be any smaller if it was made for a crop camera?

300/2.8 is 300/2.8. Unlike smaller cameras, we don't usually talk FF-equivalent with crop DSLRs so the lenses are the same.

I'm very happy with a 70-200/2.8 and 300/4 on my 7D. I like the focal lengths and I like the apertures. These would be more or less the same size if they were redesigned for crop, wouldn't they?

Also, I think Canon is probably aware that there are plenty of people buying L lenses for crop cameras. Maybe not a lot of 600mm lenses, but plenty of 300s and 70-200s based on what I've seen in use.

 

[wsmith96]

Partially agree, I think the problem is that the 1st party (Canon/Nikon/etc) view the crop bodies as consumer oriented, and so people won't spend $1+K on a lens when they can be one that looks similar for $300. Consumer mentality.

I see your point and agree. What I was meaning to say is that typically the same quality of lens is not found specifically designed for the crop cameras. That doesn't mean you can't buy a 70-200L and use it. I consider the 17-55, 15-85, and 10-22 to be "higher-end" EF-S lenses, though they don't have the L badge. But, for example, Sigma's 18-35 that's coming out - it appears to be at an L level (or above) in image quality per what I've read. I don't think that canon will make a EF-S L lens, but if they did, I do think the lens would sell. This is where I think what sigma is doing is interesting - making higher quality lenses targeted for crop cameras.

On the zooms that go over 100mm, I agree - makes no sense to not buy an EF L lens at this point in time.

 

[pharp]

Would a 300/2.8 (or anything else for that matter) be any smaller if it was made for a crop camera?

300/2.8 is 300/2.8. Unlike smaller cameras, we don't usually talk FF-equivalent with crop DSLRs so the lenses are the same.

I'm very happy with a 70-200/2.8 and 300/4 on my 7D. I like the focal lengths and I like the apertures. These would be more or less the same size if they were redesigned for crop, wouldn't they?

A 300 on a crop sensor could of course be smaller, and really smaller on a short back plane mirrorless - e.g. Olympus 75-300 is tiny (relatively) - just compare to Canon 70-300.

 

[CanonOregon]

That's very interesting as I've had the same 'dream' as well! With every new Canon lens in the $10,000+ US range, it really prices out the advanced amateur. Canon already makes some near 'L grade' EF-S lenses. A kit with a lighter, say, 400mm f4 or a 200-400 f5,6 would be absolutely fantastic for 'soccer moms and dads', weekend birders, etc. If I won a big lottery I'd put out a bounty for someone to build a lens like that if Canon didn't take it up.

 

[schill]

Would a 300/2.8 (or anything else for that matter) be any smaller if it was made for a crop camera?

300/2.8 is 300/2.8. Unlike smaller cameras, we don't usually talk FF-equivalent with crop DSLRs so the lenses are the same.

I'm very happy with a 70-200/2.8 and 300/4 on my 7D. I like the focal lengths and I like the apertures. These would be more or less the same size if they were redesigned for crop, wouldn't they?

A 300 on a crop sensor could of course be smaller, and really smaller on a short back plane mirrorless - e.g. Olympus 75-300 is tiny (relatively) - just compare to Canon 70-300.

How can the front element of a true 300/2.8 or 300/4 be any smaller than they are now? I thought the focal length and aperture of a telephoto lens pretty much determined that.

The Canon 70-300 4-5.6 is 3.0" D and 5.6" L.
The Olympus 75-300 4.6-6.7 is 2.7" D and 4.56" L.

So yes, the Olympus is smaller, but only about an inch shorter. Hardly "tiny" relative to the Canon. The Canon is also a faster lens (although they both use the same size filter, 58mm). The Canon also needs to have the IS mechanism inside (but that's a different discussion).

Based on size, I don't see a huge benefit from one to the other.

 

[Drizzt321]

Would a 300/2.8 (or anything else for that matter) be any smaller if it was made for a crop camera?

300/2.8 is 300/2.8. Unlike smaller cameras, we don't usually talk FF-equivalent with crop DSLRs so the lenses are the same.

I'm very happy with a 70-200/2.8 and 300/4 on my 7D. I like the focal lengths and I like the apertures. These would be more or less the same size if they were redesigned for crop, wouldn't they?

A 300 on a crop sensor could of course be smaller, and really smaller on a short back plane mirrorless - e.g. Olympus 75-300 is tiny (relatively) - just compare to Canon 70-300.

How can the front element of a true 300/2.8 or 300/4 be any smaller than they are now? I thought the focal length and aperture of a telephoto lens pretty much determined that.

The Canon 70-300 4-5.6 is 3.0" D and 5.6" L.
The Olympus 75-300 4.6-6.7 is 2.7" D and 4.56" L.

So yes, the Olympus is smaller, but only about an inch shorter. Hardly "tiny" relative to the Canon. The Canon is also a faster lens (although they both use the same size filter, 58mm). The Canon also needs to have the IS mechanism inside (but that's a different discussion).

Based on size, I don't see a huge benefit from one to the other.

Yes, the f-stop is related to the length of the lens and the aperture, but when a lens has to cover a smaller image circle it can be made with smaller optical elements. Can't be made really much shorter. 300mm is 300mm after all (excepting DO optics). But the elements themselves can be made smaller, which means the lens can be smaller in diameter and lighter and cheaper.

 

[Don Haines]

So now we do a little experiment....

Take a full frame lens and mount it on an APSC camera. Point it at a constant light source.... Something like a white wall under constant illumination.... You don't want something that requires precise positioning to get the same exposure... Set the camera to manual and adjust settings for the proper exposure.....

Now cut out a circle in a piece of dark paper with a hole in the center about 60 percent of the radius of your lens filter.... Place it over the end of the lens and see what happens to the light meter reading.... It drops.....about 1 stop....

This is what happens if you make the lens elements smaller.... It is light from the whole lens surface that gets focused onto the sensor, not just the center part of the lens surface... This is why a 300mm F2.8 lens is the same size no matter what size the sensor is.... Try this yourself if you do not believe me.

A crop sensor does not change the properties of a lens.... What is does is to sample a smaller area of the image circle and thereby reducing the field of view, but at the gain of a higher sampling density. The effect is the same field of view as if the lens was 1.6 times longer. A 300mm lens on a crop sensor would have the same field of view as a 480mm lens on a ff camera would have.... And yes, a 300mm F2.8 lens is a lot smaller and cheaper than a 480mm F 2.8 lens

 

[Pi]

When the 7D2 comes out the thing that would get me to buy one would be if light weight lens were available with similar quality to the L series but making use of the reduced diameter needed for the smaller sensor. (While they are at it they can reduce the price as the elements aren't as big. )

The smaller sensor (for telephoto lenses) is a problem, not a benefit. Additional glass is needed to focus the image on a smaller sensor, assuming you want the same light gathering ability. The m43 have some absurd f/2 zooms of that sort, they are monsters.

Not that there is no benefit of designing lenses for crop sensors - they can be optimized differently, and be sharper. But equivalent lenses will not be smaller of cheaper.

 

[Pi]

Yes, the f-stop is related to the length of the lens and the aperture, but when a lens has to cover a smaller image circle it can be made with smaller optical elements. Can't be made really much shorter. 300mm is 300mm after all (excepting DO optics). But the elements themselves can be made smaller, which means the lens can be smaller in diameter and lighter and cheaper.

If you want equivalent lens, it can't. It can be actually larger because it needs more or thicker elements to focus to a smaller and closer sensor.

With loss of light, it can be made smaller but then you can use slower EF lenses on your crop body.

 

[TexPhoto]

The closest comparison I can find is:

Crop - Sigma 50-150mm DC OS 76 x 135 mm 1340g - $949
FF - Sigma 70-200mm OS 87 x 184mm 1390g - $1,249

 

[schill]

The closest comparison I can find is:

Crop - Sigma 50-150mm DC OS 76 x 135 mm 1340g - $949
FF - Sigma 70-200mm OS 87 x 184mm 1390g - $1,249

150 to 200 is a pretty big difference.

 

[Mt Spokane Photography]

I used to have a 7D. A camera I took many pictures with and really enjoyed. But I was using it mainly behind L series lenses because I wanted the quality that those lenses provide. This has proved to be a good investment as I now have a 5D3 and a 1Dx and the lenses work with them.

I don't want more megapixels, I've got more than I uses almost always. And before anyone suggests it I certainly don't want more just so I can crop them away.

One of my main problems with all this kit is the weight, carrying 40Kg on a trek to a wild life photo opertunity can be a pain.

When the 7D2 comes out the thing that would get me to buy one would be if light weight lens were available with similar quality to the L series but making use of the reduced diameter needed for the smaller sensor. (While they are at it they can reduce the price as the elements aren't as big. )

I know its not going to happen but it would be nice if it did. ------- Just think a nice quality 200-400 with built in 1.4x at about 1/2 the weight and cost in front of a crop sensor giving equivalent view to a 300 to 900 on a FF. 8)

( BTW There can be little doubt that someone who thinks they know better will ridicule this idea. If they convince me that they are right I will claim I was being sarcastic ;D )

You must have quite a outfit to weigh 40KG (88 lbs). Most bodies and lenses are in the 2-3 lb category, the big whites weigh more, so if you used a lot of lenses like the 400mm f/2.8, the weight would add up.

You are asking for "L" quality, the 17-55mm IS is close. Its also big and heavy. As the focal lengths get longer, the ability to save any significant amount of weight due to smaller image circle diminishes.


A "L" quality 70-200mm f/2.8 EF-s will be smaller, but the "L" treatment with high density glass and fluorite elements will add weight. It takes more and stronger material to hold those heavy elements securely, and soon there is little weight savings and no cost savings.

IMHO, I really doubt that there is a market for a $1800 70-200mm f/2.8 EF-s lens. Most would pay the $400 extra for a FF, because they intend to get FF in the future.

Get EF-S lenses like the 10-22. and 17-55, and hope for a L treatment for a 55-250 f/4 IS lens. Any longer focal length is not very likely to happen, but up to 300mm at f/5.6 could happen.

 

[TexPhoto]

The closest comparison I can find is:

Crop - Sigma 50-150mm DC OS 76 x 135 mm 1340g - $949
FF - Sigma 70-200mm OS 87 x 184mm 1390g - $1,249

150 to 200 is a pretty big difference.

150 on a 1.5 crop is 225. on a 1.6 it's 240.
The lens was actually created and marketed as a way to get a similar range on a crop that a 70-200 provides. If you have some better examples, tell me.

 

[Pi]

The closest comparison I can find is:

Crop - Sigma 50-150mm DC OS 76 x 135 mm 1340g - $949
FF - Sigma 70-200mm OS 87 x 184mm 1390g - $1,249

150 to 200 is a pretty big difference.

150 on a 1.5 crop is 225. on a 1.6 it's 240.

Also, it is f/4.5 ( eq. to 80-240/4.5). As such, the closest comparison is the 70-200/4 IS, which is $1,150, 760 g, and well, shorter than 240mm but can take some cropping on FF and still be much better that the 50-150 on crop.

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=404&Camera=453&Sample=0&FLI=4&API=0&LensComp=804&CameraComp=736&SampleComp=0&FLIComp=3&APIComp=0

 

[Skulker]

I used to have a 7D. A camera I took many pictures with and really enjoyed. But I was using it mainly behind L series lenses because I wanted the quality that those lenses provide. This has proved to be a good investment as I now have a 5D3 and a 1Dx and the lenses work with them.

I don't want more megapixels, I've got more than I uses almost always. And before anyone suggests it I certainly don't want more just so I can crop them away.

One of my main problems with all this kit is the weight, carrying 40Kg on a trek to a wild life photo opertunity can be a pain.

When the 7D2 comes out the thing that would get me to buy one would be if light weight lens were available with similar quality to the L series but making use of the reduced diameter needed for the smaller sensor. (While they are at it they can reduce the price as the elements aren't as big. )

I know its not going to happen but it would be nice if it did. ------- Just think a nice quality 200-400 with built in 1.4x at about 1/2 the weight and cost in front of a crop sensor giving equivalent view to a 300 to 900 on a FF. 8)

( BTW There can be little doubt that someone who thinks they know better will ridicule this idea. If they convince me that they are right I will claim I was being sarcastic ;D )

You must have quite a outfit to weigh 40KG (88 lbs). Most bodies and lenses are in the 2-3 lb category, the big whites weigh more, so if you used a lot of lenses like the 400mm f/2.8, the weight would add up.


A "L" quality 70-200mm f/2.8 EF-s will be smaller, but the "L" treatment with high density glass and fluorite elements will add weight. It takes more and stronger material to hold those heavy elements securely, and soon there is little weight savings and no cost savings.

IMHO, I really doubt that there is a market for a $1800 70-200mm f/2.8 EF-s lens. Most would pay the $400 extra for a FF, because they intend to get FF in the future.

I agree with much of what your saying and don't expect it to happen.

But although I would expect the saving in money would not be much I do think the saving in weight could be significant, and in size as well come to that.


Also forgot to say, yes I'm carrying a couple of ff bodies and several big whites plus tripods flashes a hide a chair, it all adds up.

 

[Skulker]

So now we do a little experiment....

Take a full frame lens and mount it on an APSC camera. Point it at a constant light source.... Something like a white wall under constant illumination.... You don't want something that requires precise positioning to get the same exposure... Set the camera to manual and adjust settings for the proper exposure.....

Now cut out a circle in a piece of dark paper with a hole in the center about 60 percent of the radius of your lens filter.... Place it over the end of the lens and see what happens to the light meter reading.... It drops.....about 1 stop....

This is what happens if you make the lens elements smaller.... It is light from the whole lens surface that gets focused onto the sensor, not just the center part of the lens surface... This is why a 300mm F2.8 lens is the same size no matter what size the sensor is.... Try this yourself if you do not believe me.

A crop sensor does not change the properties of a lens.... What is does is to sample a smaller area of the image circle and thereby reducing the field of view, but at the gain of a higher sampling density. The effect is the same field of view as if the lens was 1.6 times longer. A 300mm lens on a crop sensor would have the same field of view as a 480mm lens on a ff camera would have.... And yes, a 300mm F2.8 lens is a lot smaller and cheaper than a 480mm F 2.8 lens

Sorry Don but I don't think your experiment makes sense. All you are doing is reducing the efficency of the lens.
How about a different approach. Think of a magnifying glass. The smaller you make the images the brighter it becomes. This is the opposite of what we see with converters. They magnify the image so even more photons miss the sensor.

The way I would look at it is that of all the photons that enter a big white a fairly high percentage hit a full frame sensor. Just a few are lost as we use rectangular sensors behind a round lens. But when that sensor is cropped to 1/1.6 of the size then only about 40perecent of the original photons are captured. (that's 1/1.6 squared for the mathematically inclined)

 

[schill]

The closest comparison I can find is:

Crop - Sigma 50-150mm DC OS 76 x 135 mm 1340g - $949
FF - Sigma 70-200mm OS 87 x 184mm 1390g - $1,249

150 to 200 is a pretty big difference.

150 on a 1.5 crop is 225. on a 1.6 it's 240.
The lens was actually created and marketed as a way to get a similar range on a crop that a 70-200 provides. If you have some better examples, tell me.

But I don't want the equivalent of a FF 200 on my 7D, I want to use a 70-200/2.8 (real numbers) which gives me an "effective" 320. A crop specific true 70-200/2.8 will not be much smaller than a FF lens.