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Old Apr 17, 2007, 6:26 PM   #11
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i think it would be more than that darren. did you change the inches to MMs ? now i'm really curious.

roy
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Old Apr 17, 2007, 6:30 PM   #12
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robar wrote:
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i think it would be more than that darren. did you change the inches to MMs ? now i'm really curious.

roy
Yes.

10"x8" = 25.4cmx20.32cm = 254mmx203.2mm

35mm is 36mmx24mm

254/36 = 7.06

203.2/24 = 8.47

So I would guess around -7.5 or -8


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Old Apr 17, 2007, 6:30 PM   #13
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the way i figured it, it's a factor 145x. about.

roy
8x25.54 = xx
10 x 25.54 = xxx
xx X xxx = a
23.5 x 15 = b
a divided by b = 145x

tell me where i screwed up

roy
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Old Apr 17, 2007, 6:32 PM   #14
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robar wrote:
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the way i figured it, it's a factor 145x. about.

roy
If a smaller sensor gives a positive crop factor ie 1.5x then the bigger sensor should give a negative factor as you get more in.

Or are you going the other way, starting with the 10x8 and comparing to the digital?


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Old Apr 17, 2007, 6:36 PM   #15
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i edited my last post.

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Old Apr 17, 2007, 6:37 PM   #16
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10'' = 10 x 25.54 = 251mm

not 25.4
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Old Apr 17, 2007, 6:44 PM   #17
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robar wrote:
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10'' = 10 x 25.54 = 251mm

not 25.4
1 inch = 2.54 cm

Therefore the crop factor is 134x


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Old Apr 17, 2007, 7:06 PM   #18
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just to confirm i understand the answer to my stupidnewbie question:

50mmFA and 40mmDA will have almost the same FOV? IE only the diff in focal length and no effect by sensor being cropped?

And 40mm will be close to human eye FOV?



oh - and what's a view camera? You don't mean those early 1900s beasts where the guy is forced to look thru the camera under a black cape do you?
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Old Apr 17, 2007, 8:54 PM   #19
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Gazander wrote:
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just so i understand it,

magnification remains the same but fov changes...?

if 3:2 aspect ratio is maintained, and you print a 35mm and dslr pic, both with the same 50mm lens.... won't the DSLR pic appear more zoomed in?
This is my sticking point with this as well. I understand that there is no magnification factor and the image on the sensor or film is the same size, just with more background. But if I actually print a 4x6 of each shot, the picture from the digital should look more zoomed in to my way of thinking.

This really does not matter a great deal to me as my interest in photography began with a digital SLR (indeed, with my point and shoot 35mm I was under the impression that higher ISO numbers simply meant "better" because ISO 400 film cost more than ISO 100 film). So I don't have to do any frame of reference to compare to anyhow. But it seems to me that some of the confusion here is whether you are thinking of the "captured" image or "printed" image when discussing the crop factor. Unless I am missing something and I am still lost?

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Old Apr 18, 2007, 12:24 AM   #20
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NonEntity1 wrote:
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But it seems to me that some of the confusion here is whether you are thinking of the "captured" image or "printed" image when discussing the crop factor. Unless I am missing something and I am still lost?

Tim
An easier way may be to take a 35mm negative, print it to 8x10" and just cut it to the 1.5 crop of the 8x10". That is what you get with a DSLR with a APS size sensor, so it is both the captured and printed image that is being discussed.

It really doesn't become much of an issue until you get into the wide angle lenses, where you will have a problem getting a wide enough FOV with 35mm lenses, which is why digital lenses are 10-18mm, which was unheard of with 35mm film.

The 8x10 film size crop factor is interesting since it isn't a crop but an expansion of the FOV and the 1.5 crop factor means that it would tak 1.5 of the APS images to make the 35mm image. So how many APS size images would it take to make an 8x10 inch sensor?

Stole this example from the net shot with a APS sensor and 35mm film with a 200mm lens.



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