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Author Topic: Digital back/camera recommendation  (Read 16257 times)

photoetude

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Digital back/camera recommendation
« Reply #40 on: December 08, 2007, 12:19:45 am »

Quote
Evgeny,

I had a little time today to try a few tests. All of no value except to say that shooting digital, I certainly don't have what is needed to get a ring near full frame and hold focus all the way at an oblique angle which is much more difficult that shooting a ring in a flat perspective or even straight down.

I spoiled myself with a 4x5, bellows and large film.

I have completely misplaced an ad I shot that was of only one ring that near filled the ad page to see what kind of focus I carried through from a film shot.

I haven't tried any digital options on a 4x5 or like body to try tilts for better in focus depth. That would require more time than I can do right now. A busy time of year.

The Canon 5D with a 100mm macro can fill the frame but not hold the ring all in focus at F32. My Mamiya 645AFD/Leaf A22 just can't get close enough with either an 80mm or 150mm both with #1 and #3 ext tubes stacked to get the ring any larger than about 1/3 of the frame height. It would require more extension. I don't have access to a 120mm macro. Not needed one yet.

If I can get time next week, I will try my Leaf with a 4x5. Granted I do not have an adapter but a black room and black out cloth can certainly "fake" an adapter to at least see what is possible.

I think the real issue is for a ring at an oblique angle to be in full focus pushes the limits of simple setups and does require a unique solution. I still don't see how any 35mm sized sensor would matter if you can't carry the needed focus in the first place. You'll just have a larger image that is still not all in focus.

I will say that a Betterlight scan back with a 4x5 and tungsten or HMI lighting would do it. Reason being the front standard can help to complete the focus issue using F64 with maybe a 210mm and the resulting file will be so damn large, you probably won't be enlarging it. So the softness from F64 won't be a big deal.

I shot with a Betterlight in 2000 and was just blown away with the files. The workflow is slow and different but the files still squash any DSLR or MFDB.

Jason's shots are quite nice, but I notice he is not carrying focus all the way through on most shots, especially those where the piece is nearing 1:1. So that is not showing a true solution for the exact purpose you need. Really nice work though, Jason.
[a href=\"index.php?act=findpost&pid=159084\"][{POST_SNAPBACK}][/a]

Hi John,
I am wondering if let say you crop 1/3 of the frame from Leaf A22 shot – how many dpi is left at 12X12 crop?
At this low magnification it should be enough DOF to cover all ring, plus
I think the Leaf A22 file can be upscaled a little bit without losing to match quality.
Please let me know what do you think…

Tanks,
Evgeny
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Morgan_Moore

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Digital back/camera recommendation
« Reply #41 on: December 08, 2007, 01:55:54 am »

As we are seeing - from johns honest 'I cant do this post' this is not easy to do with any kit.
-------------------------

Simply.

smaller chip or crop = less racking out of the bellows = more DOF for a given aperture

Therefore you need to be looking for best pixel density per dollar

which is an old multishot back



---------------

(much) more complexly

Aperture is not fixed it will be the smallest available which is a combo of

what the lenses offer

what you can light

the smallest aperture that causes acceptable diffraction.

and here is the real head scratch

There must be a complex formula of diffraction degradation as a percentage or recording area

I assume diffraction causes an equal blur at a given aperture irrelevant of recording area and therefore is less significant as a percentage of resolution loss for a larger recording area

such knowledge is beyond me but may push you in the direction of a huge chip, ie a stitching solution, and trad lenses that are operable at f64

This would require purchase of a good stitching solution and possible no new camera

the SLRc (free to you)  has the best recording size per dollar available, using stitching recording quality is less relveant because diffraction is going to limit the quality not pixel density

-------------
once again.

The client wants something 'hard to do' (also unconventional) : charge right and extend that kit budget

or

charge right for Post Production and continue with the focus bracketed approach

-------------

Thinking on further ( back to you initial post) the ring work is only a proportion of your business

As demoed you are proably after high pixel density/dollar for this 'use'

but that is not the only factor because you have other 'uses' too

ease of use for example is a factor too

and therefore the Canon1DS2.3 seems like THE CONTENDER because you are getting good pixel density per dollar and some other great stuff like AF ,non tethered, high ISO ect ect ect thrown in too

Rember a 22mp digiback has half the pixel density (approx) of the C1ds2.3 and 2 stops less ISO (?)

Even the high ISO may be a factor for the ring 'use' because at small Fs and big bellows factor you will probably run out of light on an MS back that could have an ISO of 50 or less


SMM
« Last Edit: December 08, 2007, 02:40:17 am by Morgan_Moore »
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Sam Morgan Moore Bristol UK

photo570

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Digital back/camera recommendation
« Reply #42 on: December 08, 2007, 11:18:40 pm »

Quote
As we are seeing - from johns honest 'I cant do this post' this is not easy to do with any kit.
-------------------------

Simply.

smaller chip or crop = less racking out of the bellows = more DOF for a given aperture

Therefore you need to be looking for best pixel density per dollar

which is an old multishot back

---------------

(much) more complexly

Aperture is not fixed it will be the smallest available which is a combo of

what the lenses offer

what you can light

the smallest aperture that causes acceptable diffraction.

and here is the real head scratch

There must be a complex formula of diffraction degradation as a percentage or recording area

I assume diffraction causes an equal blur at a given aperture irrelevant of recording area and therefore is less significant as a percentage of resolution loss for a larger recording area

such knowledge is beyond me but may push you in the direction of a huge chip, ie a stitching solution, and trad lenses that are operable at f64

This would require purchase of a good stitching solution and possible no new camera

the SLRc (free to you)  has the best recording size per dollar available, using stitching recording quality is less relveant because diffraction is going to limit the quality not pixel density

-------------
once again.

The client wants something 'hard to do' (also unconventional) : charge right and extend that kit budget

or

charge right for Post Production and continue with the focus bracketed approach

-------------

Thinking on further ( back to you initial post) the ring work is only a proportion of your business

As demoed you are proably after high pixel density/dollar for this 'use'

but that is not the only factor because you have other 'uses' too

ease of use for example is a factor too

and therefore the Canon1DS2.3 seems like THE CONTENDER because you are getting good pixel density per dollar and some other great stuff like AF ,non tethered, high ISO ect ect ect thrown in too

Rember a 22mp digiback has half the pixel density (approx) of the C1ds2.3 and 2 stops less ISO (?)

Even the high ISO may be a factor for the ring 'use' because at small Fs and big bellows factor you will probably run out of light on an MS back that could have an ISO of 50 or less
SMM
[a href=\"index.php?act=findpost&pid=159189\"][{POST_SNAPBACK}][/a]


All good points, which is why I went for an old multi-shot back, and am looking for more. One point though is at these sizes and working distances light is not an issue, I use a Bron Cumulight as my main light with one pack, a Primo which is only 1600w and use it mostly below half power. This is supplemented by two or three Bron minipulses which are only 300w eack, once again on half or below, at f32. The closer you have the lights, the less fall off you get.

Kind regards'
Jason Berge.
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Jason Berge
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Morgan_Moore

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Digital back/camera recommendation
« Reply #43 on: December 09, 2007, 08:18:20 am »

Quote
All good points, which is why I went for an old multi-shot back, and am looking for more. One point though is at these sizes and working distances light is not an issue, I use a Bron Cumulight as my main light with one pack, a Primo which is only 1600w and use it mostly below half power. This is supplemented by two or three Bron minipulses which are only 300w eack, once again on half or below, at f32. The closer you have the lights, the less fall off you get.

Kind regards'
Jason Berge.
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So you dont feel diffraction is an issue at f32 ?

This is a question not an accusation

(I assume you chose MS before the 1ds3)

I would however in terms of the OPs needs being studio and location think that DSLR convienience may outweigh multishot quality gains while still offering high pixel density rather than chipsize to gain MP

I dont know about the live ivew on the 1ds3 or if it even has it but the live view in 'tripod mode' onthe D3 (which I have just got) is fantastic allowing for live focus confirmation at big zooms

I cannot emphasise how well this would work on a view camera and how much shooting time it would same me compared to the poorly aligned GG I currenlty use

And of course 'time is money' is part of any economic equation

S
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Sam Morgan Moore Bristol UK

Dustbak

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Digital back/camera recommendation
« Reply #44 on: December 09, 2007, 10:26:50 am »

As promised, 4 samples that I took to compare.The ring is the one I have around my finger and the only one I currently have at my disposal. It is over a hundred years old and 23K so it got scratches. I was kind of lazy and have fastened it on styrofoam.

I used the DigiFlexII, with the Nikkor 85PC at f32 (I would normally not go beyond f16 or f22max). To get close to the ring I also used a K2, K3 & K4 (which is around 30mm). I did not go closer because I did not use macro lights but ordinary mono's (no fancy lighting). I had the PC on max tilt to extend the DoF as far as possible. ISO50, 1/125th.


I have put 4 DNG raw files on my server.

1) Imacon384, 16MP square back in single shot (cut out 2:3 and you will get the equivalent of a 11MP regtangular back).
http://www.peperkamp.com/samples/Testring001.zip

2) Imacon384, multishot (96MB's!)
http://www.peperkamp.com/samples/Testring002.zip

3) Imacon384, multishot & microstep (384MB's!!)
http://www.peperkamp.com/samples/Testring003.zip

4) Hasselblad CF39
http://www.peperkamp.com/samples/Testring004.zip


Don't bother with the exif, the Digiflex makes something really weird out of that. The settings were as been stated above.
« Last Edit: December 09, 2007, 10:35:20 am by Dustbak »
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