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10-26-2008, 04:23 AM   #31
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From time to time, when the topic pops up why or if digital MF is superior, I make the following reference:

Look up some fine art nude website (like Hegre Art) and study the samples. They are from digital MF, normally Hasselblad, and present the rare chance to study images made by this kind of camera in (almost) full size (Adam deleted links to such images I posted in the past so I won't do it now).

Tell me if you could produce similiar photos with a smaller format sensor? By similiar, I mean similiar in quality, not style

10-26-2008, 04:28 AM   #32
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QuoteOriginally posted by Boucicaut Quote
I am definitely interested in a digital MF, much more so than in a full format digital. Price has to be right, however, because I'm a hobbyist. A bare bones digital MF with weather sealing would be IDEAL. No frills, bells and whistles for me please. And, please, give us a tilt/shift lens too!

Regards,
Boucicaut
How about we lump in in-body stabilization as well? The technology's already there, just a few tweaks to adapt it for MF (or FF).
10-26-2008, 05:08 AM   #33
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tailor it to the same market as the film 645 ...

... and I'd be very tempted to buy one!

This would meen it has to be:
1. very affordable compared to other MF digital options
2. compact
3. rugged
4. relatively fast (for MF that is)

It should definitely work with the existing line-up of 645 lenses. Might only need a wider wide angle due to crop factor.

Exiting times (again?),
Torge
10-26-2008, 06:54 AM   #34
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QuoteOriginally posted by falconeye Quote
Look up some fine art nude website (like Hegre Art) and study the samples. They are from digital MF, normally Hasselblad, and present the rare chance to study images made by this kind of camera in (almost) full size

Well, I sort of loose interest in what camera has been used when looking at that sort of images....

10-26-2008, 06:58 AM   #35
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QuoteOriginally posted by torge Quote
...
It should definitely work with the existing line-up of 645 lenses. Might only need a wider wide angle due to crop factor.

Torge


Any significant crop factor will cause problems in my opinion. Apart from whine about FF (645 FF that is), the lens line isn't really large enough. You will end up with strange focal lenghts and obvious holes; popular focal lenghts that simply are missing. And there will be no strong or super wide angle. A 645 28mm/4.5 lens would be extremely hard to design and extremely expensive and have a huge front diametre.
10-26-2008, 10:22 AM   #36
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QuoteOriginally posted by Pål Jensen Quote
Well, I sort of loose interest in what camera has been used when looking at that sort of images....
Exactly what I say ... the photographs speak for themselves
BTW, Petter Hegre is a Norwegian photographer. Is he known in Norway?
10-27-2008, 05:06 PM   #37
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Nope, no interest in medium format. Lots of interest in FF 35mm dSLR. Lots of comments regarding "affordable" here, sounds like limited practical interest, since it's unlikely to be cheap if they do make a MF.
10-29-2008, 08:28 AM   #38
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QuoteOriginally posted by Pål Jensen Quote
Shallow DOF is a read herring. One in a million published images have very thin DOF and most of those would be better without it. The main problem with MF, and particularly landscape photographers, is too little DOF. Many type of images i impossible to shoot with MF because you cannot get the whole subject in focus. I rarely shoot wider than F:16 on my MF camera for a reason. The main reason for large formats "popularity" is that it gives you more DOF than MF due to the tilting function.
Are wedding and portrait photos considered published images? I guess not, however, they are very important to the people that are making a living from this business. Shallow DOF is desired for this arena. How many photographers make a living from wedding and portrait photography as compared to landscape photography? Personally I enjoy and do both types so have more than one type of camera. Of course have to agree with your comment regarding the challenge for increased DOF for many landscape shots.

10-29-2008, 09:11 AM   #39
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hmm.. i'm leaning towards 35mm FF more than MF..
I'll probably invest in old 35mm lenses as well (just in case Pentax decides to make an FF DSLR).
10-29-2008, 10:02 AM   #40
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QuoteOriginally posted by Photomy Quote
the challenge for increased DOF
When does this urban legend stop to be posted?
DoF (for a given FoV) is a function of the physical diameter in mm of the aperture -- ONLY!

The more glass, the more shallow DoF is possible.

It is not, I repeat, N.O.T., a function of the sensor format.

Except, of course, that lenses for larger formats can have, and tend to have more glass. But large lenses exist for small sensors, as well.
10-29-2008, 10:17 AM   #41
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QuoteOriginally posted by Pål Jensen Quote
Any significant crop factor will cause problems in my opinion. Apart from whine about FF (645 FF that is), the lens line isn't really large enough. You will end up with strange focal lenghts and obvious holes; popular focal lenghts that simply are missing. And there will be no strong or super wide angle. A 645 28mm/4.5 lens would be extremely hard to design and extremely expensive and have a huge front diametre.
Didn't stop Mamiya from making one for their new MF digital camera. Yeah, it costs a bunch (around 5k) but it isn't that huge for a MF lens.
10-29-2008, 10:51 AM   #42
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QuoteOriginally posted by falconeye Quote
When does this urban legend stop to be posted?
DoF (for a given FoV) is a function of the physical diameter in mm of the aperture -- ONLY!

The more glass, the more shallow DoF is possible.

It is not, I repeat, N.O.T., a function of the sensor format.

Except, of course, that lenses for larger formats can have, and tend to have more glass. But large lenses exist for small sensors, as well.
Urban Legend...NOT!! There were several extensive discussions of this issue within the last couple of months here on this forum.

From those discussions, I seem to remember circle of confusion (CoC) being part of the DOF calculation. I also recall that CoC is dependent on detection media size. If you really want to get sticky, the final display/print size and viewing distance can also factor in.

Those in doubt can simply go to one or more of the DOF calculators available on the Web:

Online Depth of Field Calculator

Julian's Lens Calculator (Also does FOV and magnification)

Or, if you don't like either of the above, click here for an exhaustive list!

Google DOF

Steve

Last edited by stevebrot; 10-29-2008 at 11:00 AM.
10-29-2008, 01:55 PM   #43
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QuoteOriginally posted by stevebrot Quote
Urban Legend...NOT!! There were several extensive discussions of this issue within the last couple of months here on this forum.

From those discussions, I seem to remember circle of confusion (CoC) being part of the DOF calculation. I also recall that CoC is dependent on detection media size. If you really want to get sticky, the final display/print size and viewing distance can also factor in.

Those in doubt can simply go to one or more of the DOF calculators available on the Web:

Online Depth of Field Calculator

Julian's Lens Calculator (Also does FOV and magnification)

Or, if you don't like either of the above, click here for an exhaustive list!

Google DOF
.......................

Steve
Nope urban legend...............
Depth of field formulae derived from geometrical optics imply that any arbitrary DoF can be achieved by using a sufficiently small CoC.................
Note nothing about sensor size
Circle of confusion - Wikipedia, the free encyclopedia
Since the final image size is not usually known at the time of taking a photograph, it is common to assume a standard size such as 25 cm width, along with a conventional final-image CoC of 0.2 mm, which is 1/1250 of the image width. Conventions in terms of the diagonal measure are also commonly used. The DoF computed using these conventions will need to be adjusted if the original image is cropped before enlarging to the final image size, or if the size and viewing assumptions are altered.

Using the so-called “Zeiss formula” the circle of confusion is sometimes calculated as d/1730 where d is the diagonal measure of the original image (the camera format). For full-frame 35 mm format (24 mm × 36 mm, 43 mm diagonal) this comes out to be 0.024 mm. A more widely used CoC is d/1500, or 0.029 mm for full-frame 35 mm format, which corresponds to resolving 5 lines per millimeter on a print of 30 cm diagonal. Values of 0.030 mm and 0.033 mm are also common for full-frame 35 mm format. For practical purposes, d/1730, a final-image CoC of 0.2 mm, and d/1500 give very similar results

NOTE all the gotchas.... and ass-umes....

Last edited by jeffkrol; 10-29-2008 at 02:00 PM.
10-29-2008, 02:13 PM   #44
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QuoteOriginally posted by jeffkrol Quote
Nope urban legend...............
Depth of field formulae derived from geometrical optics imply that any arbitrary DoF can be achieved by using a sufficiently small CoC.................
Note nothing about sensor size
Circle of confusion - Wikipedia, the free encyclopedia
Since the final image size is not usually known at the time of taking a photograph, it is common to assume a standard size such as 25 cm width, along with a conventional final-image CoC of 0.2 mm, which is 1/1250 of the image width. Conventions in terms of the diagonal measure are also commonly used. The DoF computed using these conventions will need to be adjusted if the original image is cropped before enlarging to the final image size, or if the size and viewing assumptions are altered.

Using the so-called “Zeiss formula” the circle of confusion is sometimes calculated as d/1730 where d is the diagonal measure of the original image (the camera format). For full-frame 35 mm format (24 mm × 36 mm, 43 mm diagonal) this comes out to be 0.024 mm. A more widely used CoC is d/1500, or 0.029 mm for full-frame 35 mm format, which corresponds to resolving 5 lines per millimeter on a print of 30 cm diagonal. Values of 0.030 mm and 0.033 mm are also common for full-frame 35 mm format. For practical purposes, d/1730, a final-image CoC of 0.2 mm, and d/1500 give very similar results

NOTE all the gotchas.... and ass-umes....
I have no problem with people debating the issue, but plllleeease stop with the weird colored print. It's very irritating to read to the point where I refuse to look at any postings that use it. So your point is lost
10-29-2008, 03:07 PM   #45
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QuoteOriginally posted by Alan 2 Quote
I have no problem with people debating the issue, but plllleeease stop with the weird colored print. It's very irritating to read to the point where I refuse to look at any postings that use it. So your point is lost
I use the color to seperate my words from quotes. I thought color is easier to delineate the difference.............
At dp review I usually would use dots as in (would you read it in italics and underlined???) EDIT: No italics, they ar more irritating then color
..................................................
"Edit: I should also add that changing sensor size at fixed f-stop to change the diffraction spot size relative to frame height, is really trading off DOF against diffraction effects. If you want a given DOF, the size of the diffraction spot will the the same relative to frame size; the two go together to a first approximation. Of course, it may be that the lens doesn't go fast enough on a small sensor to give the same DOF of a big sensor, but that's another issue. But given that one has chosen the DOF, that selects the f-stop (differently for different sized sensors), and the only remaining issue (apart from those of more noise on smaller sensors) is resolution, and for that, more MP is always better."..........................................



Re: The common misconception is not a misconception after enlargement: Open Talk Forum: Digital Photography Review



For those inclined to debate DOF/COC/ and the benefits of sensor size/pixel density I heartily recommend searching dpreview for Emil Martinec, John Sheehy, Gordon Goodman, Illiah Borg, Julia Borg and a host of others equally impressive and way more learned then me.....
I just try to condense it and present it. It is more valid then me just stating "Most do not need full frame, most need more pixels and better parts for the current technology (ie low noise ADC's, better cleaner circuits) and more artistic skill" or "just create with what you have and stop whining"

You people are reinventing the wheel here........
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