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Old Mar 9, 2007, 1:12 AM   #1
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Here are two photos, one shot with digital and one shot with film from about the same spot with a 50mm 1.7 lens. You can see how the crop factor works to cut some of the edges with digital that show up with film or FF digital.



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Old Mar 9, 2007, 9:56 PM   #2
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Thanks Tom. I am pretty sure I understand all of this. I understand that the crop factor affects field of view rather than focal length, but, if I understand correctly, when you are looking at two identically sized prints the crop factor has effectively changed the focal length. For example, if you took a photo from the exact same point using your film camera and a 75mm lens, it should look the same as the digital photo if both images were produced as 4x6 prints, right?

On a different note, the colors are obviously different between the two shots. As I look at your film photo, there seems to be more variety of color and greater depths of color. Is this an example of differences in dynamic range?

Thanks,

Tim
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Old Mar 9, 2007, 10:16 PM   #3
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The film was able to capture the DR from the white in the snow, to the dark inside the barn much better than the digital image did.

The K10D will take three images of one subject at three different settings and then blend them together so the final photo has the same DR as film.

I just thought it was interesting to compare the photos of the same object taken with the same lens on a film and digital Pentax camera.

The digital image seems to have some slight magnification of the buildings compared to the film image, which makes me wonder if the distance from the focal point of the lens to the sensor is the same as from the focal point of the lens to the film plane.

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Old Mar 9, 2007, 10:28 PM   #4
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Yes, I don't think these two shots really show any crop factor. They really show a different aspect ratio for the film. If you had a typical 3:2 sized print, like a 4x6, made from the film, it would likely be cropped to the same as the digital image shown.

But were they really taken from the same spot?

I see a difference in perspective. Look at the line of grass on the bottom right. In the lower picture there is much more seperation between that line of grass and the grasses along the fence. I also see more depth between the barn and the windwill behind. So it was likely taken from closer.

The digital image, with a more telephoto field of view, was likely taken from farther away to fill the frame with roughly the same subject.


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Old Mar 9, 2007, 11:29 PM   #5
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They were taken from the same spot!

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Old Mar 10, 2007, 2:03 AM   #6
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Tom,
The second picture was taken from the near edge of the road/path. The first was taken from behind the road/path.

Look at the front of the white shed on the left in the first picture. Now look in the second, your view is blocked by the same fence and bushes that were well off to the right in the first shot. The road/path which was in the foreground in the first picture, is now off to the left.

Maybe you have another sample with pictures form the same spot? This looks like it was meant to show the differnce in perspective when you frame the subject the same from farther away with the longer effective focal length.

The only thing which changes perspective is distance from subject.

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Old Mar 10, 2007, 4:11 AM   #7
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why is the snow cyan in the first one?
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Old Mar 10, 2007, 9:36 AM   #8
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The snow is blue because I didn't process the photo and in the winter around here snow shows up blue unless you PP the image.

I did not use a tripod, but I did take both photos from the same spot (possibly a 5 foot difference after I got done changing lenses from my bag) on the same day, but the angle of view difference is correct.

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Old Mar 10, 2007, 9:50 AM   #9
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ennacac wrote:
Quote:
The K10D will take three images of one subject at three different settings and then blend them together so the final photo has the same DR as film.
This is the same thing that HDR software does, right? I did not know tha the K10 could do this in camera also. Now I want one even more. Can you only do this with RAW or can you perform the same combination of three images in Jpeg mode?

Thanks,

Tim
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Old Mar 10, 2007, 8:23 PM   #10
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Which image is film and which is digital?

I'm not sure why, but the barn appears to be standing straighter in the top photo as compared to the bottom. :-)
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