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Author Topic: Resolution  (Read 13322 times)

Eric Myrvaagnes

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Resolution
« Reply #20 on: May 27, 2005, 01:53:53 pm »

I just had two of my best 6x7 trannies high-res scanned, and compared with the same shot taken with my 10D (not even a 20D). And sectional blowups to 16x20" show no more detail and no greater dynamic range in the 6x7s than from the 10D.  ???

Anybody want to buy a great Pentax 67 II kit with lots of good lenses?    

Eric
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Jonathan Wienke

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« Reply #21 on: June 01, 2005, 05:08:23 pm »

The camera may (or may not) select an arbitrary PPI number to tag the RAW with, but it's completely meaningless, and frankly not even worth wasting oxygen thinking about. You have total freedom to override this tag at any point in your workflow. It's much more useful to simply think of digital images in terms of pixels instead of physical dimensions like inches or centimeters, since a digital image file has no physical size whatsoever. Only prints have a physical size, and the pixels/inch or whatever are only determined when you send the print job to the printer. Any tags in the file are completely meaningless until then, and most of the time afterwards as well. There is no reason a print has to have any correlation to the Pixels/inch or pixels/cm tag in the image file. It's merely lucky happenstance if it does.
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peter2005

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« Reply #22 on: June 29, 2005, 03:13:20 pm »

MarkDS, absolutely. I wonder why Nikon said that, I understand that not all professional cameras makers give this possibility. Anyway, the main doubth that my group discussion could have with Jonathan's post was if you can set the photograph resolution before you take it or before the photograph is transformed in a spectrum of pixels , the reply for me is clearly NOT but not for them and I wouldn't be able to solve them this doubth without your post. Thank you very much indeed
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peter2005

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« Reply #23 on: July 05, 2005, 04:30:14 pm »

So you can also resize in the raw converter, but in the same way that you would do in any other software, and always after taking the photo. It's something more to learn. Thanks
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peter2005

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« Reply #24 on: May 24, 2005, 05:10:22 pm »

Thanks for reply, Jonathan, and can you tell anything about first question? Does digital image itself have resolution as we know (px/inch or px/cm) or itself have only size (px)¿¿??
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peter2005

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« Reply #25 on: May 25, 2005, 10:27:36 am »

Jan, sorry english isn't my mother tongue, with "All of these contribute to the illusion of resolution, so that the number of pixels doesn't even tell half the story" you mean that even we would able to find the resolution concept in the physical sensor of the camera, it probably only adds confusion because digital image doesn't have resolution (like px/mm) ¿?
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Jack Flesher

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« Reply #26 on: May 25, 2005, 12:09:09 pm »

1000px x 1000px is always 1000px x 1000px, which will always be 1 million pixels or 1 MP...  

1) It does not matter what the diameter of those pixels are for that comparison.  However,

2) Now enter different diameters for pixels.  If a set of pixels is twice the diameter of another, they will require a chip with 4x the area to hold the same number.

3) With the larger AREA of the chip and 2xs the diagonal, you will need a lens with 2x the focal length to get the SAME field of view with the two image systems.  

(I believe concept #3 is the resolution hurdle where folks get confused.)

4) Soooo, both chips have the same resolution but different image-sensor sizes and hence require different focal lengths to get the same picture.  IF you now try to "compare" the cameras using the SAME lens, the sensor with the smaller pixel diameters will be able to offer greater DETAIL, assuming the lens can accomodate it, but the resultant image will be as though you cropped the center from a chip with 4X the resolution.

Hope this helps,
Jack
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Dinarius

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« Reply #27 on: May 26, 2005, 01:15:32 pm »

My Canon 20D RAW conversions at 300 PPI end up as near as dammit to A4 in size.

Am I right in understanding that, if I *know* that my images are never going to be used larger than A4, I don't gain anything by shooting for the same size print on, say, a PhaseOne?

Or is it the case that, because the P1 native size is greater, if it is reduced to A4, the resolution would be better?

Thanks.

D.
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jani

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« Reply #28 on: May 26, 2005, 06:18:14 pm »

Quote
90% of what I do rarely goes above A5, never mind A4, so I guess I can stick with my 20D then.

I put the question of size to a bunch of photographers recently, and they agree with me. Most of what they do stays A5 or smaller.

Who needs PhaseOne!? ;-)
I see the smiley.

I don't know about a PhaseOne back, I have nothing to attach it to (unless it magically fits that No. 2 Folding Cartridge Hawkeye), but I'd really love to do prints as wide as A1 or A0 that I could stand a foot away from and still not see all the details in.

And I'd like to do those kinds of prints with as little stitching as possible.

Well, I can dream, can't I?
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Jan

peter2005

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« Reply #29 on: May 31, 2005, 06:39:08 pm »

Can anybody tell me if in the RAW conversion setting you can set resolution (in px/inch, px/cm or whatever it be)? Thanks in advance
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dlashier

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« Reply #30 on: July 03, 2005, 04:19:22 am »

Quote
ut I would like to know the purpose of this taging because this point has been cause of discord in same recent discussion. In other words, I would like to see as detailed as possible. because taging the raw is meaningless and you can override this tag at any point in your workflow, is there any purpose on it like for example the default resolution (px/inch, px/cm,..) for printing after?
The only reason for tagging is to offer an option of showing out size in real dimensions - eg. inches or centimeters. You must specify resolution (pixels/physical-measurement) in order to mathematically convert from pixels to measurement (inches etc), and carrying along a tag can simplify the workflow assuming it is appropriately set.

Think back to HS math - dimensional analysis. "Pixels" is dimensionless. In order to convert to a dimensioned value (inches) a conversion factor is required, in this case pixels/inch. Size(inches) = pixels / resolution, or dimensionally analyzed inches = pixels / (pixels/inch) = pixels * inches/pixel, and the pixels cancels leaving you with inches.

- DL
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peter2005

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« Reply #31 on: June 01, 2005, 06:32:02 pm »

I totally agree with you Jonathan, but I would like to know the purpose of this taging because this point has been cause of discord in same recent discussion. In other words, I would like to see as detailed as possible. because taging the raw is meaningless and you can override this tag at any point in your workflow, is there any purpose on it like for example the default resolution (px/inch, px/cm,..) for printing after? Thanks indeed
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Mark D Segal

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« Reply #32 on: July 05, 2005, 01:25:21 am »

Don, the reason I said that is because whether you dimension in RAW or dimension in PS, you are still at one stage or another deriving inches from pixels as a function of resolution, and as you say - where you do it is a matter of personal preference. Your arithmetic is of course correct and, as I am sure you would acknowledge, complements what I was explaining to the gentleman about how these relationships work, differentiated by whether or not one resamples the image.
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Mark D Segal (formerly MarkDS)
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