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10-08-2010, 05:58 AM   #16
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QuoteOriginally posted by Digitalis Quote
I suggest he do the complete opposite..how many times did Ansel Adams ever photograph a wall? I would say that is extremely unlikely he tested his lenses the way you are suggesting it would be a criminal waste of time. I certainly don't obsess over the performance of my lenses. And I was taught to use an 8X10 camera by my grandfather who did his best to impress upon me the tenets of the f64 group.

what I would do is just go out and take photos that I like to create, if I came across an issue with the sensor/lens experiment, then I would learn how to control or eliminate it. I don't subscribe to doing the ridiculous amounts of "testing" people spend most of their time doing, With new lenses I just do a basic resolution,vignetting,distortion and flare test - that's all that really matters.
Boards and Thistle for one from Ansel Adams. Devil's Postpile for two, Shards of Glass for three, White Post for four, Self portrait in Utah for five, Political Sign for six, Billboard for seven.... and on and on. You can't control a sensor that's not aligned. You have to return the camera for repair. The subject is not the issue, using a flat plane to make a test is.

You seem to be missing the point of doing a simple set of tests to prove quite easily, after spending multiple thousands of dollars for a set of equipment, that your equipment works correctly. Why would you want to discover on a photo trip that your equipment was defective? Do you think that Ansel Adams didn't know absolutely that every piece of his equipment worked perfectly before he went to Alaska for six weeks? What's wrong with doing a simple set of tests? Sure you can make tests by doing what you like.

Ansel Adams and Minor White and others from f64, applied stringent craft, (and that included testing of multiple parts of the photographic process), to their art. Both Adams and White were adamant that a "bohemian" approach to photographic craft was not to their liking.

As Ansel Adams said and I quote"Craft facility liberates expression".

If you're having a problem with my suggesstion go to Joseph Holmes Natural Light Photography Home Page and read his article on the problems with medium format cameras, lenses and sensors. By the way Ansel Adams called Joe's color work "a revelation".

And a note: I've only used a 4x5 since 1983. You can see my work in one of three monographs: Wilderness of Light, Chronicle Books, A Vast and Ancient Wilderness: IMages of the Great Basin, Chronicle Books, and Yosemite Once Removed: Portraits of the Backcountry, The Yosemite Association.

Claude Fiddler

10-08-2010, 04:57 PM   #17
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QuoteOriginally posted by claudefiddler Quote
You can't control a sensor that's not aligned. You have to return the camera for repair. The subject is not the issue, using a flat plane to make a test is.
And you bring up ansel adams and 4X5 view cameras which have been known to have issues with film flatness..um, we are talking about a digital medium format SLR here, with quality control that is worth a damn, at least It should be for a $10,000 dollar camera.

I'm just pointing out that learning what the lens is capable of is more important than the sensor, when I got my K10D I stuck a 31mm f/1.8 on it and used only that lens for three months, I did the same thing with My K-7 and FA77 f/1.8 limited. I used to to photograph 645 colour film, I would always shoot colour checker charts at the beginning of the roll to give me some colour reference in my commercial and portraiture work, but I didn't go much further than that because the more time you waste obsessing over things the less time you have to actually make images in the field, in the end you will learn far more about your equipment than any test will.

I agree that "Craft facility liberates expression" but from the way I see it doing countless "tests" and obsessing over lens/sensor performance has very little to do with craft.
10-08-2010, 08:28 PM   #18
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Dear Digitalis

Yes quality should be worth a damn at 10K. Unfortunately the fact is that it is untrustworthy at even higher prices. Joe Holmes saw almost 50% failure with sensor alignment and lens sharpness in the system he tested.

You can have a tack sharp lens but if you get images that are out of focus, as our original contributor did, how are we to know where the problem lies? Harklee's example points to an AF that might not focus where he intends or the need to stop down further and does not appear to be a sensor problem. But who knows without another.....test.

You yourself point to some need to make a confirmation about lens performance and film color.

Would you keep a faulty piece of equipment. There's no work around for a misaligned sensor or soft lens, or auto focus that does not work, or manual focus that's not accurate. Would you practice your craft with faulty equipment. Would a mountaineer head up Mount Everest with a broken ice axe?

The result is going to be bad photographs or worse on Everest. Who would abide an image that's not perfect from a new 645D. I assume Pentax wouldn't. I wouldn't. I'm guessing you wouldn't.

I saw a brand new Alpa, Phase, Rodenstock set up that would focus on 600 feet instead of infinity at the infinity setting. I had a Canon something point and shoot, I can't remember, out of the box, with a sensor misaligned so the left side of the image was out of focus. Bad quality control from the top to the bottom of digital equipment is what I've seen.

I never had a problem with film flatness with film holders or ready loads. Roll film is where that problem usually occurs.

I'm not talking about obsessing on tests. I would not have made six trips to the Brooks Range in Alaska, climbed to 27,500 feet on the West Ridge of Mount Everest, set the world speed climbing record on the Salathe Wall of El Capitan in Yosemite or had four books published if I was obsessing about testing. But I sure as hell knew my equipment would not fail and was tested over and over again.

You're right, this did happen through many years of use. What I'm advocating is a get off on the right foot approach.

I have had the harsh lesson of not testing, been on a long trip and gotten what I thought would be stellar photos, only to find the spot meter wasn't working right and I had worthless sheets of film.

I'm not into countless tests. It seems we'd both agree that there's way too much emphasis placed on the tech side of photography. I think what you're pointing to is how some people get totally hung up on analyzing, looking at or making tests to the point where they forget what it is they're supposed to be doing. That being taking pictures.

I for one am still waiting for a decent set of, you guessed it, tests from the 645D so I can evaluate it's performance. That probably will only happen when I get my hands on one.

And then I'll spend half a day testing and I sure am hoping that what's revealed is a superb camera and lens. I truly want this system to work out.

Re lens performance as it pertained to Ansel Adams and Edward Weston: Adams writing to Weston: "As for the lens trouble you write about....I think what you want for your best solution is the Zeiss Protar No.6, 19 in....This lens is quite light in weight. You could always add the second element to it (or have a set of elements to use singly or in combination). The Protar....cannot enlarge as many times as the Dagor but for contact and moderate enlargement it cannot be excelled....."

Edward Weston was unhappy if not obsessed with a particular a lens' performance. You can argue how they went about their testing but it's obvious ( otherwise why bother with the in-depth comparison by way of testing) Ansel Adams and Edward Weston very much considered lens performance important to their craft and art and I do too.

Lastly, I don't care if someone takes my words to heart. I 'm not writing a photo rule book or trying to be a photo process judge. To each his own. I should have made it more clear that what I'd like to see is, or what I would do is.....but it's Harklee's camera and lens to do with as he sees fit. What matters to me are superlative images, regardless of means.

I apologize for being pushy.

Claude Fiddler
Wilderness Light

Last edited by claudefiddler; 10-09-2010 at 07:20 AM. Reason: two words in a row
10-08-2010, 10:29 PM   #19
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Claude,
Welcome to the forum. I am familiar with your work and am pleased to see you posting here. The photographers on the Pentax forum are an enthusiastic and talented bunch with a significant number heavily involved in film and larger formats both in and outside the Pentax system. While there are many viewpoints on technique and style, the competence level is pretty high and the atmosphere collegial. I am looking forward to your contribution.


Steve

10-09-2010, 12:36 AM   #20
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QuoteOriginally posted by claudefiddler Quote
I never had a problem with film flatness with film holders or ready loads. Roll film is where that problem usually occurs.

I have had sagging issues with some some plastic film holders I had provided from one studio, and certain backs for medium format typically had to be tweaked to enhance flatness (the bronica SQ-A comes to mind) though of course the Estar base on large format film has considerable rigidity, unfortunately it was far too thick to be used on rollfilm. Though I recall t-max was pretty thick - which was a mixed blessing because it could damage winding mechanisms.


QuoteOriginally posted by claudefiddler Quote
I for one am still waiting for a decent set of, you guessed it, tests from the 645D so I can evaluate it's performance.
And so am I, the Kodak sensor is being used in the current series of hasselblad and Leica medium format cameras albeit at a somewhat lower resolution 37/39Mp VS 40Mp so their technology is a known quality, Kodak typically rate their sensors pretty conservatively. I have seen the white paper from kodak on this particular sensor and from what I have seen from my own use of a Phase one camera back it should be pretty damn good (and with a superior LCD I might add). What will be of most interest for me is how the 645D will work with my Pentax 67 800mm f/6.7 ED on it.

Last edited by Digitalis; 10-09-2010 at 12:43 AM.
10-09-2010, 12:43 AM   #21
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Thanks for posting Harklee, nice to see it being used in anger. For what it's worth, my first shots with a new camera are usually disastrous, these things just take a little getting used to
10-09-2010, 05:05 AM   #22
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QuoteOriginally posted by claudefiddler Quote
Diffraction doesn't matter in a big print. I've never seen it and I used f 32 and 45 plenty. If you need f22 you need f22. Who wants a blurry image. And you bought the 645D to make big prints, right? I only used a 4x5 because I wanted to print to 32"x 40". Otherwise I would have used a 35mm camera.
I have seen diffraction many times and with a 40Mp sensor in the 645D at apertures past f/11 it will become obvious. I work with diffraction limited lenses and with these lenses there is a marked difference between performance at widest aperture -f/5.6 and f/11 when using a 39Mp digital back.

QuoteOriginally posted by claudefiddler Quote
I saw a brand new Alpa, Phase, Rodenstock set up that would focus on 600 feet instead of infinity at the infinity setting
I don't mean to sound irritating, but exactly what is infinity focus?
10-09-2010, 07:15 AM   #23
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Infinity focus is a subject that has no near or middle ground. For instance, the summit of a peak one quarter mile away. With the 4x5 in this for instance, one would focus on the peak and there would be little or no bellows draw.

Not being familiar with medium or 35 systems, this would mean turning the focus ring of the lens to the infinity marker, or in a preferred set-up to the infinity stop (the lens has no travel left) where one was assured that the summit of the distant peak or whatever was in focus. I'm guessing that this was/is a feature of older manual focus lenses. You're probably much more versed than I with these camera systems and could bring me up to speed on lens function.

For me at least this is an important issue as a lot of what I do is infinity focus. Infinity focus would also seem to be pretty important for stitching as one could maintain the same plane of focus during the stitching process. I've only experimented with stitching a few times and at the present don't intend to use it.

My intent with the 645D is to use a legacy telephoto with tele-converter. If the AF lenses don't have an infinity stop I may opt for a manual focus lens. Stick with MF you might say, but my eye-sight is not what it once was and I would prefer to rely on an AF system. The 4x5 got harder to focus with glasses on and off.

And like you Digitalis I prefer to work with a single set-up. I had a 150mm Rodenstock parked on my Linhof IV. I didn't use another camera or lens for two decades and had only one other lens, a Nikkor 300mm. I used the 300 twice in that twenty year period and finally sold it.

Hope this answers the question.

Claude Fiddler
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10-09-2010, 07:25 AM   #24
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I know what infinity focus was I was just curious on what your interpretation of it is, ask an astrophotographer and you get an even more technically involved answer. As a landscape photographer I have used stitching quite a bit with superb results, though it is highly dependant on subject matter.

Most telephoto lenses designed for SLR use focus past infinity in order to compensate for heat expansion that occurs with the materials used to construct them. my 67 800mm f/6.7 ED focuses quite a bit past that mark and most shorter lenses 100mm and above share that trait. From what I have seen the Viewfinder of the 645D is much larger and brighter than current pentax DSLR cameras it is a bit puzzling that although the 645D isn't full frame 645 it's viewfinder still has only 98% coverage. The original 645NII was absolutely superb in terms of film economy and in features.
10-09-2010, 11:59 PM   #25
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Thanks for the comments and informative discussions. I am gonna have to take some other time to understand all the details, but here is another sample from tonight. Weather was really boring, so it was a good chance to run some more tests. This one was taken at Marshall's beach, San Francisco, California, I didn't even bother to save the highlights by manual blending, so it's pretty much straight from the camera. The 645d seemed to handle 2-3 min long exposures pretty well, and the quality of images is very promising. Since I was shooting at 75mm and still wanted to include a close rock in the foreground, this time I decided to stop down to f/18 and carefully examined the details to fine tune the focus after taking a few sample shots. Taken at ISO 200(default), f/18, 75mm, 2 stop soft GND was used. Will provide some other samples soon.

- Resize


- Crop #1



- Crop #2

Last edited by harklee; 10-10-2010 at 01:16 PM.
10-10-2010, 12:16 AM   #26
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Without wishing to drag this further from the original subject, the QC on your average Lisco or Fidelity holder wasn't that great and your film plane wasn't necessarily straight, nor parallel to the GG. The best of the "cheap" holders was the Grafmatic, since the septums held the film straight (harder for it to "pop") and the spring system did a better job of holding it parallel to the GG position. Better still are the vacuum back systems, but much more expensive. And the Astro guys used glass plates.
10-10-2010, 12:34 AM   #27
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excellent images though I notice some unusual flare appearing at the top right of the frame,apart from that the resolution is excellent even it if is somewhat lessened by diffraction.


"Without wishing to drag this further from the original subject, the QC on your average Lisco or Fidelity holder wasn't that great and your film plane wasn't necessarily straight, nor parallel to the GG. The best of the "cheap" holders was the Grafmatic, since the septums held the film straight (harder for it to "pop") and the spring system did a better job of holding it parallel to the GG position. Better still are the vacuum back systems, but much more expensive. And the Astro guys used glass plates."

I agree, but My grandfather was never the type to do things cheaply and he was the person who taught me 8X10 camera technique. For my ebony 8X10 camera I used their custom wood film holders made by Lotus, which hold the film snugly and obtain excellent film flatness. Though for my Sinar and Horseman cameras I had to muck about finding ones that were anywhere near as good, fortunately Lotus can make wood holders for Horseman and Sinar cameras - at a cost. I have used plates before, though that has been a very long time ago for me but they were completely impractical to use in the field.
10-10-2010, 03:13 AM   #28
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QuoteOriginally posted by Digitalis Quote
I suggest he do the complete opposite..how many times did Ansel Adams ever photograph a wall? I wou
Not enough...
10-10-2010, 07:50 AM   #29
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Thank you Harklee.

I think the flare on the right side could be caused by the bright lights below the bridge casting light upward. The flare has a straight line on the right side. Probably caused by a part of the bridge directing the light. This bright light also seems, (I cant see this on my monitor for sure) to be blowing out the highlight on the bridge pylon. I'm glad you didn't try to save this highlight. I think its more valuable to see how many stops of range the camera can handle. Did you happen to figure out how many stops of range were in the scene?

By the way, you probably know this, with a long exposure you could have used your hand (moving it in front of the lens) to burn down the sky and the bridge highlight. I used to use the dark slide of a film holder with the 4x5 to burn down all sorts of highlights in the camera. Worked, for me at least much better than an ND as I didn't get the weird gradations that can happen with an ND. Like a tree in a sky region that's black in the ND area and obviously lighter below.

The GND filter makes it harder to evaluate dynamic range capability. Where did you place the GND. It looks like you did a great job as the bridge towers don't have an obvious lurch in tone scale.

Shadow detail looks okay but it's hard to tell how sharp it is.

Bridge tower detail looks to be there. But under the bridge, those dark shadows don't appear to have detail, except where they're lit by bridge lighting.

Distant lights of Sausalito appear to have detail but like the shadows hard to tell how much.

Thanks again,

Claude Fiddler
www. wildernesslight. com

p.s. Mom used to take me to Marshall's and Ocean Beach as a toddler.

p.p.s. The following spec page shows ISO 100. Is ISO 200 the lowest ISO setting? https://www.pentaxforums.com/forums/pentax-medium-format-slr-camera-reviews/9...ntax-645d.html Also, if you're interested LLoyd Chambers www.digglloyd.com does what are, in my opinion, excellent camera/lens tests. His tests cut to the chase in in terms of performance and allow one as Keith Richards puts it "get on with the show".

Last edited by claudefiddler; 10-10-2010 at 08:32 AM.
10-10-2010, 03:20 PM   #30
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Thanks, Harklee, for doing a exposure longer than 30 seconds. If I had that camera, I'd definitely be shooting in the 2 minute range frequently and was really wondering about it.
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