Hi, I'm trying to find a table with lens crop factor for leaf digital backs, but for some reasons all this information is hidden from a user.
Anyone knows the numbers? thanks
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Hi, I'm trying to find a table with lens crop factor for leaf digital backs, but for some reasons all this information is hidden from a user.
Anyone knows the numbers? thanks
AptusII 8 uses a 43.9x32.9 sensor, this gives you lens factors of:
1.28 on 645 bodies e.g. Mamiya 645DF
1.44 on 6x6 bodies e.g Hasselblad 503CW
1.63 on 6x7 bodies e.g Mamiya RZ
2.96 on 4x5 cameras (with 4x5 lenses)
Hope this helps
Yair
Yair Shahar  Product Manager  Phase One  Mamiya Leaf
e: [email protected]m  m: +44(0)77 8992 8199  yaya's blog
Check this out: http://www.captureintegration.com/?s...gth+calculator
Put the focal length in under your specific back/sensor size and it'll give the focal length equivalents across many formats. Very helpful to my "stuck in 35mm"mind.
Isn´t that a bit misleading to distinguish different crop factors for medium format systems. The 80mm of the classic 6x6 should give the exact same angle of view (and crop factor in regard to the digital back´s sensor size) as does the 80mm lens of the 645 system. The factor only differs in respect to the original film format ratio.
Or am I confusing something here?
Oliver
For the Leaf II 8/P40+ to get 35mm equivalents divide the actual lens focal length by 1.46. Or put another way it's a 1.3x (1.28x) crop compared to full frame 645 as Yair quoted.
Remember: adventure before dementia!
As Oscar Wilde said, "my tastes are simple, I only like the best"
The elephant in the room—as I see it—is the feasibility of comparing different aspect ratios (usually 35mm’s skinny 2:3 to squarer, larger formats). I always work from the short side of the frame, assuming a print sized at “normal” 3:4 and 4:5 ratios; 35mm frames are always cropped lengthwise to fit these dimensions.
So if you want to compare, say, the AptusII 8 to 35mm fullframe, the multiplying factor (rounding up) from 35mm is 33/24 = 1.375 — the other direction is 24/33 = 0.73 (rounded).
The lens’s image size,* DOF etc. will be the same on any camera at the same focus point, but the horizontal and vertical field of view covered will vary with the frame size. So an 80mm lens on a Mamiya 645 film camera will show a bit more subject than with a smaller digital sensor, such as the 33 x 44 Leaf mentioned (a tenth of a millimetre? Gimme a break!
But put the same lens on a 35mm fullframe camera and it’s a longfocus lens (not necessarily a telephoto!).
*By image size, I mean the scale of the image.
Last edited by mediumcool; 9th August 2011 at 03:22. Reason: added a word
It's based on the diagonal of the format. If you crop for equivalent aspect ratio then of course the diagonal changes and hence the equivalency factor for crop purposes.
In all other aspects though an 80mm lens is an 80mm lens regardless of sensor size or format as far as optical characteristics are concerned.
I would agree though that for strict format comparisons there's a little more to it than pure multiplication factors. After shooting 4:3 for a long time 3:2 always feels like an ungainly aspect ratio ... I'm still a sucker for the square format so that probably makes me a dinosaur.
Remember: adventure before dementia!
As Oscar Wilde said, "my tastes are simple, I only like the best"
Let’s face it, the 120 square format was perfect for LP cover shots! CDs too.
I remember a longago client wanting a 35mm negative printed to 10" x 8", and becoming very stroppy when I mentioned that there would be white strips top and bottom if I didn’t trim the print to 6 and twothirds inches. Nowadays it’s easy enough to distort the image.
Last edited by mediumcool; 9th August 2011 at 04:01. Reason: spelling
Size of sensor is known. Apart from laymen cams that is all that seems needed
I suggest that best is to understand how to calculate for you to know exactly and visualize exactly compared to other format. At times I compare both for vertical and horizontal. How else to compare e.g. 617 to 645 format lens visions?????
To calculate is very simple
Here are two examples;
(1) Compared to 645:
44x33mm sensor vs. 56x41.5mm > 56/44=1.27
(Here I picked horizontal, does not matter, since both 44x33 and 56x41.5 is 4:3 proportion sensor)
(2) Compared to 6x6:
44x33 sensor vs. 56x56mm
by width: 56/44=1.27
by height: 56/33=1.70
by diagonals:
sqrt(56x56+56x56)=79
sqrt(44x44+33x33)=55
> 79/55=1.44
(Here I looked at all, since 6x6 is square and 44x33 is 4:3 proportion)
Most important: What I actually calculate to compare is the equivalent lens focal. If I know I like the vision of e.g. an 80mm lens on 645 but want to know what equivalent I should use on the Aptus 8 sensor in order to achieve same view, thus 100mm x 44/56 = 63mm
Whichever you use is up to you and exact how you wish to compare.
Yair Shahar  Product Manager  Phase One  Mamiya Leaf
e: [email protected]  m: +44(0)77 8992 8199  yaya's blog
Btw, once you know how to calculate for diagonals it's trivial to calculate for shifts as well. For example, if you have a 44x33mm sensor and are able to use a 10mm shift or rise in each direction the you can calculate focal length equivalents for a 64x33mm, 44x53mm or even 64x53 for multiaxis shift for the stitched image.
Remember: adventure before dementia!
As Oscar Wilde said, "my tastes are simple, I only like the best"
thank you.
Thierry Hagenauer
[email protected]
Thierry,
Here's a shameless plug for the Alpa mother of all calculation spreadsheets that I use:
http://www.alpa.ch/en/products/tools...alculator.html
It's not as simple as the Capture Integration worksheet but if you use shifts, tilts, DoF calculations etc it's ALL here.
Remember: adventure before dementia!
As Oscar Wilde said, "my tastes are simple, I only like the best"
Thierry Hagenauer
[email protected]