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Author Topic: Testing P65+ for architecture tomorrow.  (Read 15628 times)
marcwilson
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« Reply #20 on: March 20, 2009, 12:17:47 PM »
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Quote from: GBPhoto
My usual method is to also shoot an unshifted shot, then align the two in PS.  That way I have a lens-center reference for correcting distortion and CA.  I have this all running as an action, so it's pretty painless after getting it set up.


Just trying to get my head around this method...and it's not working late on a friday afternoon here in the UK!
Would you mind giving a fuller explanation?

Cheers,

Marc
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Kirk Gittings
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« Reply #21 on: March 20, 2009, 12:36:22 PM »
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"I was looking to buy that current TS 24mm, but as Canon announced to release new TS lenses soon so i just looked at one of the new TS lens, but i am looking to try to find many job in architecture and interior design photography in my country, and you know most of them are looking for large print for posters or billboard, so what i can do if i can't afford higher MF and LF bodies?"

I actually think there is no better way to learn AP than buying and learning to use a 4x5 VC. I agree with GB about that-it teaches discipline.

Having said that, as per DSLR and  posters and billboards. I doubt most of your images will be used that large. Most in fact will probably be used on websites, magazine spreads, PowerPoint presentations or notebook size design proposals. A 21 MP camera is fine for all of that and more. But you could shoot a billboard with a 5MP camera and uprez it, many have. The viewing distance is so great on billboards that fine quality is lost. As per occasionally needing a large poster? Know your clients specific needs and learn to stitch with your DSLR.
« Last Edit: March 20, 2009, 12:40:20 PM by Kirk Gittings » Logged

Thanks,
Kirk

Kirk Gittings
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marcwilson
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« Reply #22 on: March 20, 2009, 12:58:37 PM »
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Thanks Alan.
Very well presented!

Presumably you note amount of shift / rise for each shot and then align the shifted image to the unshifted image by that amount.

Marc
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Kirk Gittings
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« Reply #23 on: March 20, 2009, 01:18:11 PM »
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Quote from: GBPhoto
I used to before I included the zero-shift frame.  The unshifted frame eliminates the need for note-taking, always a bonus!

Adding a zero shift frame, great idea.
« Last Edit: March 20, 2009, 01:20:52 PM by Kirk Gittings » Logged

Thanks,
Kirk

Kirk Gittings
Architecture and Landscape Photography
WWW.GITTINGSPHOTO.COM

LIGHT+SPACE+STRUCTURE (blog)
marcwilson
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« Reply #24 on: March 20, 2009, 01:21:34 PM »
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So you simply always align the shifted image to the far end of the shift / rise (canvas).
Really simple idea Alan.

Thank you very much for sharing this and I'll give it a go next week to see the results.

Cheers,

Marc
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eronald
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« Reply #25 on: March 20, 2009, 01:27:13 PM »
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We ran out of tripods before we ran out of cameras



Edmund
« Last Edit: March 20, 2009, 01:27:37 PM by eronald » Logged
marcwilson
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« Reply #26 on: March 20, 2009, 01:33:29 PM »
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so with all those camera angled upwards...I guess lots of p.s. work for those converging verticals.
« Last Edit: March 20, 2009, 01:33:50 PM by marcwilson » Logged

JdeV
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« Reply #27 on: March 21, 2009, 05:07:58 AM »
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Quote from: marcwilson
so with all those camera angled upwards...I guess lots of p.s. work for those converging verticals.
Nope. Making things look pretty wasn't the point. Since we didn't have perspective correction on the Hasselblad it wasn't used on any of the cameras for this test.
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marcwilson
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« Reply #28 on: March 21, 2009, 06:06:21 AM »
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Quote from: JdeV
Nope. Making things look pretty wasn't the point. Since we didn't have perspective correction on the Hasselblad it wasn't used on any of the cameras for this test.

Fair enough, but doesn't using shift affect the final image quality from these digital backs, which is of course not the case in film which it was being tested against, especially bearing in mind the end usage..architecture?

Marc
« Last Edit: March 21, 2009, 06:07:37 AM by marcwilson » Logged

JdeV
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« Reply #29 on: March 21, 2009, 06:12:38 AM »
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In the end we shot an interior of the Gare de Lyon station with a lot of signage, cast iron and glass roof etc. and an exterior of the Frank Gehry designed  Centre Cinemateque Francais in the the Parc Bercy. (Forgive my French spelling if I got any of that wrong).
We used:

P65 on Hasselblad H2 with 50mm and 100mm lenses.
P45+ on Mamiya with 55mm lens.
D3x with 24mm shift but also with 24-70mm zoom lenses.
Arca Swiss Monolith 8" x10" with 240mm lens Apo Symmar and Kodak Portra 160NC.
Toyo VX125 5" x 4" with 120mm Super Symmar HM and Kodak Portra 160NC, 400NC and 100G transparency.

All lenses were set on their optimum apertures. All exposures were exactly the same. As far as possible all shots were done at exactly the same time. However, we only had four tripods so the P45+ was shot a minute or two after. Framing was matched as closely as possible. The Nikon was shot in 5" x 4" mode. Digital files were processed in Capture One but the Nikon files were also processed in Aperture. The film was scanned by Core in London on a Screen 1045i by a very good, very experienced scanner operator.

The 8" x 10" has not been scanned yet.

What have we learned so far?

1. The P65 and the P45+ seemed to just out-resolve drum scanned 5" x4" negative film. It's something of a tie with the transparency.
The Nikon with either lens was significantly behind in resolution. There was quite bad CA on the 50mm Hasselblad lens but it was slightly sharper than the Mamiya 55mm. There didn't seem any substantial resolution advantage to the P65 over the P45+.

2. General colour and tonality of the digital files seemed broadly more accurate than the film, though the film had a pleasing 'film' look to it with the transparency probably most pleasing of all. Moire/weird colour artifacts on the LED train announcement board was horrendous with the P65 and bad on the P45+. At the station there was also a green neon cross in front of a pharmacy and a neon sign above a cafe which were bad on the medium format backs with the P65 worst. These issues would be difficult to fully resolve in retouching. The Nikon had some colour artifacts on the announcement board but managed the neon pretty well. Overall the Nikon probably provided the most neutral, accurate colour. The P65 on the Hasselblad and the P45+ on the Mamiya have a significantly different colour feel between them.

3. The difference between the 160NC and the 400NC was so miniscule that for scanning purposes you might as well only shoot 400NC. (When conventionally printed there is a contrast difference equivalent to a 1/4 stop pull going from the 160NC to the 400NC but this is an extremely minor correction to make on a scanned file).

I'm off to China for a two week architectural commission but will try to add further comments when I get back. I will have the 10" x 8" scans by then.
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JdeV
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« Reply #30 on: March 21, 2009, 06:27:08 AM »
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Quote from: marcwilson
Fair enough, but doesn't using shift affect the final image quality from these digital backs, which is of course not the case in film which it was being tested against, especially bearing in mind the end usage..architecture?

Marc
You are absolutely right. As you and others have pointed out it would have been better to test with a proper digital view camera set-up.
However, I couldn't get one in the time available and because I had never shot architecture with a digital camera there was a lot that I could learn by doing so even with regular medium format bodies. (I shoot architecture/travel intermittently but at a reasonably high level. My regular practice over the last ten years or so has been mostly to shoot 5" x 4" or 10" x 8" negative and print it myself. The client being supplied with 16" x 12" or 16" x 20" prints. (I would also sometimes shoot transparency)).

What I now need to do is shoot with a digital back and a view camera with a bunch of lenses on it's own. I don't need to compare with film or 35mm digital any further at this stage having learned a great deal from this test.
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eronald
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« Reply #31 on: March 21, 2009, 07:24:58 AM »
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In this test I supplied the Mamiya with 55 shift and the new gen 24mm Nikon shift lens. Jonathan who is an experienced architecture specialist chose his angle and subject matter. We may make files with scans available when the 8x10 scans come in.

In this test we don't really have an immediate  "winner", because the looks differ immediately, while the resolution differences only come into play as you scale up the magnification by a HUGE amount.

All the cameras seem to have DR sufficient for this type of imaging. I'd say the upshot is that factors other than simple sensor resolution which now come into play - primarily lens quality, and tripod stability,  and Raw development and sharpening. My impression is that the Mamiya and Nikon lenses are outresolved by the sensors they are attached to.  One thing Jonathan and I agree on is that the P45+/Mamiya combo is doing better than we both thought it would, both in resolution and in "look".
 
I'd say that what we need these days is better lenses even more than better sensors. We're going to try and match the Phase back with a high-quality view-camera lens in a reshoot.

Edmund
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jsch
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« Reply #32 on: March 21, 2009, 01:10:17 PM »
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Quote from: GBPhoto
My usual method is to also shoot an unshifted shot, then align the two in PS.  That way I have a lens-center reference for correcting distortion and CA.  I have this all running as an action, so it's pretty painless after getting it set up.

Hi,

I use the same method for capturing. But I enlarge the canvas always to the full image circle and correct distortion in PTLens. See:
http://www.epaperpress.com/ptlens/index.html (-> click "shift lenses" in the navigation on the left side for full explanation).

I tried to remove the distortion in PS lens correction but the results were worse than PTLens.

How do you remove distortion?

Best,
Johannes
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RobertJ
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« Reply #33 on: March 21, 2009, 05:09:22 PM »
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Looking forward to some crops/images from the test, as well as the results from the 8x10" film...
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georgl
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« Reply #34 on: March 22, 2009, 04:39:31 AM »
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I'm excited to see the results!

But no clearly visible resolution advantage 39MP->60MP and digital->4x5" ? It would have been interesting to see how the Rodenstock/Schneider-lenses perform on the 65+ (every review was made with Mamiya/Fuji-lenses till now).

Some simple math:

4x5" @ 40cycles/mm (2000ppi) = 8000x10000pixels actual resolution = 80MP

40cycles/mm are not much and can be reached at lower contrast even with faster film - when the images were focused precisely and scanned properly?

What is the scan resolution (lower resolutions like 2000ppi will cause grain alaising and lower overall contrast at higher frequencies, better scan at 4000ppi and downsample to 2000ppi).

Anyway, thanks for the test!
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brianc1959
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« Reply #35 on: March 23, 2009, 07:08:58 PM »
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Quote from: georgl
I'm excited to see the results!

But no clearly visible resolution advantage 39MP->60MP and digital->4x5" ? It would have been interesting to see how the Rodenstock/Schneider-lenses perform on the 65+ (every review was made with Mamiya/Fuji-lenses till now).

Some simple math:

4x5" @ 40cycles/mm (2000ppi) = 8000x10000pixels actual resolution = 80MP

40cycles/mm are not much and can be reached at lower contrast even with faster film - when the images were focused precisely and scanned properly?

What is the scan resolution (lower resolutions like 2000ppi will cause grain alaising and lower overall contrast at higher frequencies, better scan at 4000ppi and downsample to 2000ppi).

Anyway, thanks for the test!

In practice, its probably not so easy to print details from 40lp/mm on a 4x5 negative.  I always routinely shot (have to admit the past tense here) 4x5 at f/22 or slower to get the depth of field I wanted.  At f/22 the contrast at 40lp/mm will be ~35% even for a perfect lens.  Multiply 0.35 by the MTFs for film, scanner, and printer (or alternatively film, enlarging lens, and paper), and you have practically zero information at 40 lp/mm.  Given this, I'm not too surprised that 39mp or 60mp digital would put up a good show relative to 4x5, but like you I'm really curious to see the results of the actual test.

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georgl
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« Reply #36 on: March 24, 2009, 04:56:36 AM »
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I also suspect diffraction and depth of field as crucial.

f5.6 is a good aperture in 645-digital for this kind of work, 4x5" would need f11 to gain the same amount of depth of field (MTF for most lenses at 20lp/mm 70% just 10% worse than at f5.6 with most Fuji-lenses of the H-System >50% picture height) and 8x10" would need f22 which would cause serious diffraction problems even at 40cycles/mm - in theory...  

But we have seen enough horrible film vs. digital comparisons (remember "11MP-1ds beats 6x7 Velvia"!?) and comparing 4x5" with diffraction (f22) scanned at 2000ppi somewhere in the focus plane with the sharpest spot in a 60MP-digital-file would lead to similar results.  

If 4x5"/8x10" is always feasible just because it propably has more resolution is a different story...
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BJNY
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« Reply #37 on: March 24, 2009, 07:30:30 AM »
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I'm curious about what you guys are saying,
except I'm not comprehending,
especially with the word "cycles" being used now.
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Guillermo
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« Reply #38 on: March 24, 2009, 11:45:23 AM »
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Quote from: BJNY
I'm curious about what you guys are saying,
except I'm not comprehending,
especially with the word "cycles" being used now.

One cycle = one line pair.

If you're familiar with a line pair, it's a dark line followed by a light line.

Looked at mathematically, it's a graph representing density on the vertical axis which swings low (dark line), then high (light line), like a sine wave (ideally a square wave).

Regardless of shape, this repeating pattern can be referred to equivalently as either a line pair or as a cycle (one swing low, then high, and returning to the start postion).

-Brad
« Last Edit: March 24, 2009, 11:49:10 AM by bradleygibson » Logged

BJNY
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« Reply #39 on: March 24, 2009, 12:30:27 PM »
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Thanks, Bradley.

However, I don't know what a line pair is.

What are you guys saying in non-scientific terms?


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Guillermo
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