The heck with the crop factor....

[adan]

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Marquinius--yes, but only in terms of depth of field....

 

I knew it couldn't last...(sigh!)

[ho_co]

With a wider lens, the distortion increases towards the edge of the image, so if you crop the image, the distortion is less noticeable. I would be very surprised if anyone could tell the difference between a cropped image taken with a 35 Lux on a full frame and an uncropped image taken from the same point, with a 50 Lux. I would think they would be more likely to spot the differences between an image taken with a 50 Lux and a 50 Sonnar. ...

Wilson, I agree fully.

 

But, with respect, the formulation that "the distortion increases towards the edge of the image" is not accurate. The phenomenon is a common observation, but the description is wrong.

 

I don't want to be picky (though I shall ), but what people refer to as "wide-angle distortion" is nothing more than a discrepancy between the point of view of the observer and the point of view of the camera when the picture was shot. (Since 'distortion' is a lens property, a better term would be "perspective exaggeration," but even "perspective exaggeration" is not quite right because the only thing 'exaggerated' is the difference between the lens' viewpoint and ours when we view the image from a "normal" distance.)

 

This was drilled into me early in my curmudgeon training by John Brooks of the New Jersey Leica School: He showed us a print from a shot by the Hologon, if I remember correctly, made from very close to a group of people. Everyone agreed that "wide-angle distortion" was present, with bodies and heads stretched toward the edge of the frame.

 

Next, John put a 35 mm (maybe 50 mm) lens on a Pradovit and projected the original of the same image wall-size: The people in the image were now full people-size, not diminished on paper. We walked up to the image, standing about three feet from the wall/screen. And guess what? They looked normal.

 

It has to do with point of view only, and with duplicating the taking distance with the viewing distance.

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[dm1127]

i disagree with the assertion that you would not notice the difference between images shot with a 35mm cropped and a FF 50mm. the compression of a 50mm in relation to the background of the image is far more dramatic than a 35mm. if you should wide angle lenses, it's quite apparent.

 

i've become accustomed to the crop compromise. i will be glad when it's over, and someday LEICA must make a full frame M, but for now i am very happy that i can shoot my leica glass on a LEICA made digital body. i love the camera.

 

some examples: Flickr: darin moran's Photostream

[ho_co]

I knew it couldn't last...(sigh!)

Andy, it's a great topic.

 

And as a couple people have said, it depends on the individual. In other words, IMO, everyone here is correct.

 

-- You can't duplicate the look of a favorite lens by using a different one.

-- Choosing the right lens has to do with what the photographer sees. (In that regard, see Zoom - Errol Morris Blog - NYTimes.com for January 25, "Mirror, Mirror, on the Wall," a very interesting piece on photographs of the Bush Administration.)

-- If you're shooting landscapes (living in Denver, say ), you can choose a lens based on how it feels to you.

-- If you're doing portraits, you'll either have to change your working distance or change your lens.

-- There's no logic to the Barnack format. Like the length of a 35mm film, it was just convenient using the materials of the time. Any other size would have been fine. But today it's the only 'norm,' since all the crop factors are referenced to it (and there's nothing 'standard' about those numbers--1.33, 1.3, 1.5, 1.6 for example). Nothing right or wrong about it, but "it's what we know." So a manufacturer has a big plus if he can say, "With me there's no crop factor" (even if his lenses aren't all that good).

 

And if it works for you, then do it. I'm glad Andy posted this thread because I'm glad to see so many points of view on a topic that we'll never fully get to the bottom of.

 

In my case, my most-used focal length pre-M8 was 28 mm. With the M8, I use the 21 because it 'sees' the way I'm used to. (My 28 and 21 are both quite early and share the less harsh pre-ASPH "Leica look.") I used to use the 75 Summilux quite a bit, but with the M8 my shooting has changed and although I use the 50 Summilux more now than I did, I tend to go quite a bit wider than before, and shoot almost exclusively 21 mm and shorter. Different tools, different pictures. Know what you want to shoot and choose the lens for the job. And since we all want to shoot differently, we'll all have different views on choice of tools.

[ho_co]

i disagree with the assertion that you would not notice the difference between images shot with a 35mm cropped and a FF 50mm. the compression of a 50mm in relation to the background of the image is far more dramatic than a 35mm. if you should wide angle lenses, it's quite apparent.

Darin, welcome to the forum! You can always tell it's an interesting thread when you see a number of first-time or seldom- posters join in! Glad you feel like speaking out!

 

The important point here is blowing up the cropped image from the 35mm to the same size as the full image from the 50. It isn't immediately obvious that the two images should be the same, and it was hard for me to get my head around it when the LFI article on Peter Karbe's presentation mentioned it. I had to read the article three times before I thought I understood it, and I still wouldn't be able to recount the logic.

 

But the point is that a smaller sensor has increased depth of field because it's smaller, nothing more nor less. When you blow it up, the enlargement process effectively decreases the depth of field.

 

In other words, from a given standpoint, all lenses must exhibit the same perspective because the rules of physics don't allow light rays first to ask what focal length lens they're going to enter, and then to vary their paths accordingly.

 

There are some very competent people on the forum who will capably pull out depth-of-field charts and tables and formulas to pick holes in this idea. But the formulas are approximations based on approximations. You can carry them out to millionths of a micrometer, but since they started with approximations, the apparent accuracy disappears.

 

Similarly, though Karbe's assumptions begin with strict physics, they also end up abbreviated to a rule of thumb. (When I said above that a 50 on the M8 behaves like a 66.67 mm lens, the statement made a point but was meaningless both because we don't know the actual focal length of the "50" (most M so-called 50s are closer to 52 mm) and because 4/3 is irrational when expressed as a decimal.

 

As for the practical point you make: Could you in fact tell the difference between the 50 and the 35 images? Maybe you could, because the lenses are different (as Wilson said, you might more easily be able to distinguish between a Sonnar and a Summicron) and because in your example, they use different parts of the sensor. Therefore, the laws of physics will have different effects on the light rays--the rays from a face, say, will impact the sensor closer together with a 35 than they will with a 50, causing differences in resolution, diffraction, etc. And that still doesn't take into account the fact that the pixel pitch will likely be different between the two examples. (I think the Nikon D3 and D3x are the only cameras that would allow the comparison with the same pixels.)

 

But theoretically, given perfect focus and given perfect resolution from sensor and lenses, there would be no difference between the two lenses.

 

I think it's necessary to look at this kind of discussion as a thought experiment and to consider its application.

 

And "consider its application" bears within it the concept that a photographer doesn't have to understand all this unless he's asked to separate Saddam Hussein from his body doubles.

[Marquinius]

I knew it couldn't last...(sigh!)

 

Steve & Ho_Co: thanks, this makes it perfectly clear.

 

Adan: no worries, we'll stay out of DOF and stick to this very interesting thread.

 

Marco

[ho_co]

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Hey, now wait a minute, Marco! You didn't ask me, now did you?

[Marquinius]

Gnnnh gnnnh gnnnh

[Rolo]

I appreciate that for maximum value comparative lens tests need to be scientifically done. However, I don't have scientific tests to offer. Dismiss these comparisons if you chose, but my intent is only positive. The shots were not from from the same position, but quite near.

 

The first image is show the coverage by a 24mm Elmarit with on film and then on the M8 (inside). Shows the effect of the crop fairly dramatically, IMO.

 

The second shows the 35mm on the M8 with the 50mm film FF overlaid (inside).

 

Hope this adds to the debate.

 

Rolo

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[pgk]

Out of curiosity, how many people actually take the same photo from the same spot with equivalent lenses on two different formats and then print them up identically? Let me guess.... not many I'd say. Discussions like this are all very well, interesting enough, but fundamentally academic! Given the M8's format, most M film shooters will simply accept the crop factor, adapt to is vagaries, and get on with taking photos.

[ho_co]

BTW--One way to look at the question of focal lengths is to use a zoom lens. When you go from tele to wide, you get more stuff at the edges, but there's no change in the image perspective.

 

Then just imagine that you crop the edges at one or several points along the zoom.

[positivibes]

I also use my favorite Lens Combo from Film (24/35/75) on my M8. I only added the cv15 as superwide. And i find my self using the same lenses for the same situataions as i did on film. The crop didn't change a thing.

[BerndReini]

Boy, why is this so difficult to explain? No you don't change the perspective if you don't change the vantage point when you zoom, but why do that? Either you want Grandpa's feet in the shot or you don't. If you do, then you will change your vantage point and thus the perspective when shooting with the M8 vs a full frame camera. I agree that we adjust to the crop factor, but we do so by either walking further away from the subject or by using a different lens, so it does matter. Or do some people here simply not care what they want to contain within the frame? The sample images above are a perfect example. Take the bottom one: either you want the top of that red tower in the frame or not. With the M8, you have to step back, and you are thereby changing the perspective. Now if that doesn't matter to you, that's fine, but you cannot say that it doesn't make a difference. It changes what your picture looks like, and not just in terms of quality or depth of field, but perspective, i.e. how different elements within the frame relate to each other.

[Double Negative]

There's more to a lens than just field of view; as the OP suggests, each lens has a variety of factors that combine to form its "signature."

[ho_co]

Bernd, as you and pgk say, you handle the image differently depending on the lens, or (the other way around), you choose the lens differently depending on the subject.

 

I think I've been part of the confusion, because there are at least two different topics being discussed.

 

First is the question of whether one goes on shooting with the same lenses (which requires making changes in shooting style). And the second, intruding topic is the matter of how subject, perspective and lens choice interrelate.

 

Since we've got people speaking to both points, often without mentioning which they're addressing, the thoughts seem to get muddled.

 

 

In regard to the crossover between the two trains of thought, I find posi's comment from a couple posts ago telling:

I also use my favorite Lens Combo from Film (24/35/75) on my M8. I only added the cv15 as superwide. And i find my self using the same lenses for the same situataions as i did on film. The crop didn't change a thing.

Although he says, "I [still] use my favorite Lens Combo from Film (24/35/75) on my M8," he goes on to add that "[he] only added the cv15 as superwide." That might have happened even without the move to M8, but it definitely did with the reduced sensor size.

 

In other words, the addition of the wider lens would fit into the argument that the cropped sensor forces a rethink of one's lenses. (I'm not saying that the smaller sensor forced the addition of the Heliar, just that the event is open to that interpretation. )

[tgray]

Ignoring lens signatures, for me to get along with a crop camera, I'd have to adjust the focal lengths of my lenses. The two most important factors for me in selected lenses is the field of view it provides (focal length + format dependent) and the perspective I want, which is dictated by the situations I'm in. Combining the two gives me my focal lengths for a given format.

 

As a result, if I went to a 1.3 crop factor, I'd have to shift down in focal lengths, because I want the same field of view *and* the same perspective, which means taking the appropriate steps back won't be sufficient.

[pgk]

In other words, the addition of the wider lens would fit into the argument that the cropped sensor forces a rethink of one's lenses.

 

OR

 

If you still operate with your existing lenses, then this forces a rethink as to how you use them. And, given that you already have them then its easy enough to find out which alternative works for you - empirically.

[fotografr]

I have honestly never given any thought to the crop factor. I just look at what I want to shoot, then see what's in my bag and put on the best lens for the shot. Not much to it. Any lens use involves a compromise in some way or another. Maybe a 17mm would be perfect for a landscape, but there isn't a 17mm, so you adjust. Or maybe a 63mm would be ideal for a portrait. One isn't made, so you adjust.

[larry]

I have honestly never given any thought to the crop factor. I just look at what I want to shoot, then see what's in my bag and put on the best lens for the shot. Not much to it. Any lens use involves a compromise in some way or another. Maybe a 17mm would be perfect for a landscape, but there isn't a 17mm, so you adjust. Or maybe a 63mm would be ideal for a portrait. One isn't made, so you adjust.

 

Brent,

 

Adjust, horrors -- that would mean you are cognitively flexible! Didn't you know that Leica users should never be flexible or change?

 

Larry

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[fotografr]

Brent,

 

Adjust, horrors -- that would mean you are cognitively flexible! Didn't you know that Leica users should never be flexible or change?

 

Larry

 

Did I forget to mention my memory is going?