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06-27-2008, 09:11 AM   #16
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Well, since dSLRs were originally meant to compete with 35mm film SLRs, then it's just obvious to tell the new dSLR users what their images will look like compared to the same lens on their old film SLR. Hence, the 1.5 crop factor.

Nothing sinister about it. Just an artifact of transition of technology. Since I never really used a 35mm SLR, I just ignore the crop factor. I just want to know type of image (and field of view) the lens will produce on my K20D.

I'd suspect it's here to stay for a while, given that more and more camera companies are starting to offer full frame dSLRs while still selling APS-C dSLRs.

06-27-2008, 10:20 AM   #17
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QuoteOriginally posted by Wheatfield Quote
There is no "crop factor". When will people wake up and realize this?

Thanks, I just had to get that out of my system.
True. But when you're comparing the new standard (aps-c) to the old standard (35mm) and most of the lenses being used right now cover the old standard, then it makes sense to refer to a 'crop factor'.
06-27-2008, 10:43 AM   #18
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I sometimes call it Capture Angle though Field of View is perhaps better. The subject has some relevance for me because I still shoot 35mm film sometimes, almost always with a 28mm f2.8 AIS lens on my Nikon FM3a. I like the coverage but the shortest Pentax lens I own is the 21mm DA and the FOV with that lens is "equivalent" to about 31.5mm. Not far off but still not the same.

"Crop Factor", "Field of View", or whatever you want to call it has little relevance to anyone who never shot 35mm film. But I would still like a Pentax prime that gave me a "Field of View" of 28mm AND matched the quality of my Nikkor. I really like the 21mm DA but my Nikkor is in a class by itself. Put a bright light source in the frame with the Nikkor and you see absolutely no flare or ghosting. Really great for sunset shots. Not so the 21mm DA.

Richard
06-27-2008, 10:53 AM   #19
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QuoteOriginally posted by Old Timer 56 Quote
I sometimes call it Capture Angle though Field of View is perhaps better. The subject has some relevance for me because I still shoot 35mm film sometimes, almost always with a 28mm f2.8 AIS lens on my Nikon FM3a. I like the coverage but the shortest Pentax lens I own is the 21mm DA and the FOV with that lens is "equivalent" to about 31.5mm. Not far off but still not the same.

"Crop Factor", "Field of View", or whatever you want to call it has little relevance to anyone who never shot 35mm film. But I would still like a Pentax prime that gave me a "Field of View" of 28mm AND matched the quality of my Nikkor. I really like the 21mm DA but my Nikkor is in a class by itself. Put a bright light source in the frame with the Nikkor and you see absolutely no flare or ghosting. Really great for sunset shots. Not so the 21mm DA.

Richard
I had the same problem until I bought my Sigma 10-20mm .

The widest lens I owned was the Pentax FA-J 18-35. 18mm is not overly wide on a DSLR with ASP-C sensor, equivelent to 27mm FOV on a 35mm frame, and I already had a 24mm which I had decided was not wide enough, but the 18-35 was a full frame lens, so all my ultra wide shots were on film using my PZ-1 with the FA-J 18-35.

06-27-2008, 11:09 AM   #20
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I would say that given the number of people who have used 35mm Film Cameras, the term "crop factor" has a great deal of significance when referring to the product of a lens on an aps-c camera.

The OP asks if those who used 4x5 or 6x7 see what was produced by the 35mm camera as a crop factor. I'd say that 99.99% of the people who have shot in 35mm have never seen, or used, a 6x7 or 4x5 camera. So, that argument is irrelevant.

As far as the DA series of lens are concerned, the F/L remains the same so the product will have the "crop factor". Whether, or not, the Da could be used on a 35mm camera is also not relevant.
06-27-2008, 11:13 AM   #21
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QuoteOriginally posted by Wheatfield Quote
I seem to be on a mission this morning.
Yeah, you are. And you have an agenda. You probably like APS-C and dislike FF. However, you overshoot here

The crop factor applies to certain DSLR bodies -- NOT lenses! It is named the way it is because it says what it is, i.e.:

If you mount a 35mm lens onto a DSLR body, you must divide the 35mm field of view by the crop factor to determine the resulting field of view.

If somebody gives you a DSLR body and a lens, you need to know the bodies crop factor (because it isn't standardized, except with the FourThirds-System -- which is why I agree with you that 2.0 is NOT a crop factor).

Some bodies have a crop factor of 1, some 1.3, some 1.5, some 1.6. You always need to know. And there is nothing wrong with the naming.
06-27-2008, 11:15 AM   #22
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I like it when people use "Focal Length Multiplier". That's about as wrong as you can get it.
06-27-2008, 12:15 PM   #23
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QuoteOriginally posted by falconeye Quote
The crop factor applies to certain DSLR bodies -- NOT lenses!
Exactly.

And the reason for it: After decades of shooting 35mm film photographers had become so accustomed to the film's FL-FoV relationship that they figured FoV not in the angle but instinctly via the FL number eg. 28 is wide, 50 is normal, 100 is 2X tele ...

Now with a smaller image sensor this relationship changes; in fact it's the FoV that changes but photographers didn't work with the old angle numbers what hope is there to get them converted to the new angles. More convenient to rely on Equiv FL purely as the "old-money" number representing that particular FoV.

06-27-2008, 01:02 PM   #24
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QuoteOriginally posted by Wheatfield Quote
... Why not think of the format in it's own terms, rather than applying the rules from a different format and then applying a multiplication to get back to the format you are using? ...
Fair enough point, but the short answer is that most of us come from a 35mm format frame of reference, so to help us translate, it "works" to compare what a 200mm lens would do on a 35mm film camera w/ what a 300mm lens will do on a digital camera w/ an APS-C sized sensor.

It is like people who live in countries that use the metric system. They say to us backward United Staters, "The metric system is so much easier to convert, to understand the relationship between measurements of volume, weight, and distance, etc." I reply, "You're correct, of course, but it's not the simplicity of the old system that keeps us hanging on to it; it's just what we're used to. We know what 64 degrees F feels like, but when you say, 'It's 18 degrees C', we don't know what that feels like."

So, your point is logical, but that doesn't necessarily mean everyone will say, "Let's stop talking about a 'crop factor' & just get used to 300mm on APS-C sized sensors!"

Maybe you should take consolation that people are using "crop factor" rather than the completely erroneous term "magnification factor" to describe the same thing.
06-27-2008, 01:14 PM   #25
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Well, I had a 35mm camera back in 1980 and used it for fun for about a year before getting into Medium Format (6x7) and then I shot pro for about 20 years, but only with the 6x7 (portraits, glamour and headshots) and 4x5 and 8x10 (product photography), when I went digital in 1998, it was a 3-pass scanning back on my 4x5 camera. So I am most familiar with angles of coverage, working distance, DOF, how much I can tilt or shift and not vignette, etc.. and the focal lengths I prefer in these formats.

When I got into DSLR in 2001, I immediately had to sit down and figure out what lens for my Canon D30 would give me the same focal effect and working distance as my RB180 lens on my 6x7, and what lens I could use for some product shots that would be close to my 150 on my 4x5 back. But even back then I noticed that the exact translation from my 8x10 or my 4x5 camera to my RB67 didn't always produce the same look and feel, even though it gave me the exact same crop at the exact same working distance. I preferred to leave it a bit shorter on my 6x7 to match up better, even though I had to come in a bit closer. With my DSLR, even though my RB180 lens would be the same cropped field of view at the same distance as say a 60 for the Pentax DSLR. I prefer a longer length, say 70 or 77 and with Canon their 85, as it did not translate directly exactly to what I used to shoot with my RB, and even though I have to shoot from a bit farther back to get the same area covered, the overall look is more similar.

I believe that the crop factor is more or less for figuring out angle of coverage and field of view and not meant to translate directly into how a lens will behave. Put a fisheye lens on that Olympus DSLR with the 2x crop factor and while mathematically it seems like it would now be a moderate wide angle, but the images will still look like they were taken with a fisheye.
06-27-2008, 01:27 PM   #26
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I'm with russ. I think of things it terms of small sensors. If I ever get a FF camera, I'll be lost.

As for misnomers, what do you call a computer? It grates on my nerves when people call it a "hard drive." But "CPU" is pretty widely accepted, despite being just as incorrect as "hard drive."
06-27-2008, 04:08 PM   #27
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QuoteOriginally posted by joefru Quote
what do you call a computer? It grates on my nerves when people call it a "hard drive." But "CPU" is pretty widely accepted, despite being just as incorrect as "hard drive."
???
computer, hard drive, CPU are three entirely different beasts and I haven't yet met somebody who would mix the three terms up. Like a car, a wheel and a motor are hardly ever mixed up... So, I don't get your point.
06-27-2008, 04:08 PM   #28
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Most of us refer to the reduced sensor size as a crop factor,because we are used to the 35mm format and this is an easy way of explaining the differences in lens selection for a job. I personally find it insulting to have crop factor referred to as mushy thinking. After all it is only samantics. As long as you grasp the differences in formats, it shouldn't matter how we get there. They used to call it the image multiplier and that was changed to keep the nit pickers happy.

Dave

QuoteOriginally posted by Wheatfield Quote
Out of curiosity, what is the "crop factor" of a DA70mm LTD? Or a DA14mm, or a DA 12-24, or a 21mm LTD, or the DA200 and 300 mm lenses. They aren't usable on 35mm, so why reference back to that format.
06-27-2008, 06:03 PM   #29
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Even before dslrs it was hard to figure out what lenses would give the same field of view on two different formats like 35 & 6x7. Wonder if photography didn't make a huge mistake years ago using focal length to define a lens? What if lenses came in field of view markings? Like a fisheye would be a 180 etc. Just use 1 diagonally measured number to describe each lens. Just a thought.
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06-27-2008, 07:15 PM   #30
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QuoteOriginally posted by barondla Quote
Even before dslrs it was hard to figure out what lenses would give the same field of view on two different formats like 35 & 6x7. Wonder if photography didn't make a huge mistake years ago using focal length to define a lens? What if lenses came in field of view markings? Like a fisheye would be a 180 etc. Just use 1 diagonally measured number to describe each lens. Just a thought.
Then people would say "my 180 is actually a 120 on my new DSLR".
And they would complain because they were getting less.....
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