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2-1/4 x 3-1/4 Standard Lens testing

 
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troublemaker



Joined: 24 Nov 2003
Posts: 715
Location: So Cal

PostPosted: Fri Jan 11, 2008 9:01 am    Post subject: 2-1/4 x 3-1/4 Standard Lens testing Reply with quote

I started making some comparisons of a few of the standard lenses I have for the medium format Graphics.
I'll list them tomorrow when I have more time.
So far I did a harbor landscape comparison and just did a quicky lens test chart shoot with the same group one shot each for center resolution at f~16. So far the 103mm Trioptar is slightly besting 101 and 105 Ektars, 101 Optar and Raptar, 105 Xenar, and 101 Graflar. Where I can just make out the line splits at 40 lpmm for the Trioptar, it is 34 or less for rest (viewing about a forty inch enlargment witha grain scope). But I intend to re-shoot the line chart test with more attention to lighting camera support and developing. Then I'll shoot each at f~11 and 22.
Interestingly, at the end of the roll I made one test shot with a 65mm 6.8 Angulon I just acquired to see if it is any better than the Wolly 65 Raptar I was trying to use. According to the test chart it's resolving somewhere between 34 and 40 lpmm. Right there with the better standard lenses. And it made some nice images down at the harbor. 16x20" enlargements should be nice and much better 11x14.
Anyway, if anyone has any suggestions regarding using the line test chart or otherwise let me know.
I gleaned as much as I could from the info shared by Chris Perez, but I doubt anything I've done so far is nearly as objective...
And while I am not concerned with the edges or coverage just yet, I do intend to make one comparison with each lens wide open.


Last edited by troublemaker on Fri Jan 11, 2008 9:07 am; edited 1 time in total
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Henry



Joined: 09 May 2001
Posts: 1439
Location: Allentown, Pennsylvania

PostPosted: Fri Jan 11, 2008 4:27 pm    Post subject: Reply with quote

Excellent, Stephen! You're doing us all a great service. Just curious: how does the 101 Optar compare with the 101 (?did you mean 103?) Graflar? Also, same question for the 65 Angulon vs. Raptar.
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Dan Fromm



Joined: 14 May 2001
Posts: 1881
Location: New Jersey

PostPosted: Fri Jan 11, 2008 4:46 pm    Post subject: Reply with quote

So your shooting a USAF 1951 chart? Good for you.

But why don't you examine the negatives directly instead of enlarging?

I ask in part because brightness (is that the right word?) has a big effect on what one can discern. I hit this in a big way when struggling to focus on a USAF 1951 on glass at high magnifications. It all got much easier after I got a better lighting setup.
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Henry



Joined: 09 May 2001
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Location: Allentown, Pennsylvania

PostPosted: Fri Jan 11, 2008 4:55 pm    Post subject: Reply with quote

[quote="Dan Fromm"]

But why don't you examine the negatives directly instead of enlarging?

Well, maybe because we exhibit prints as enlargements; I've yet to see a framed negative in a gallery, except as part of a historical exhibit (such as the current one at MMA). IMO counting lines on a negative doesn't mean anything unless it translates into viewable superiority. YRMV.
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troublemaker



Joined: 24 Nov 2003
Posts: 715
Location: So Cal

PostPosted: Fri Jan 11, 2008 6:53 pm    Post subject: Reply with quote

I only had one exposure left at the end of the first roll, so I decided to compare the Angulon's resolution to the lenses I was already testing.
I do intend to compare to the 65 Raptar.
As I said, this and the landscape shots were a preliminary.
Next I'll spend a lot more time insuring the best possible results with the line chart test and also more outside work.
I didn't spend much time on the preliminary line target test, used too long of an exposure, and had the tripod way too high to insure best possible results for each lens.

I am testing a Graflar 101. I believe these are Rodenstock glass, made in Germany. I'd think what you have from your emails is the earlier Wollensak 103mm Graftar mounted on the Century shutter. Two very different animals.
The Gralfar was available on the later model Century cameras mounted on a Prontor SVS shutter.

The 101mm Raptar and Optar tested about evenwiththe uncoated 101 Ektar and 105 Ektar. Of the Ektars, the 101 coated is best. The German Graflar, though the negs look better due to nice contrast, when enlarged, it was not as good as the U.S. glass. (which one of the resons for the testing is to cherry pick the best standard lens to take on trips and backpacking).

Also, I don't see how else I can tell much about the line test pattern looking at negatives, but I'll take a look later. I doubt I can dicern much without enlarging 30" or larger. These are the better lenses I have to choose from. They all make excellent negatives and look sharp unless enlarged big.
The line test pattern will give me information I can pass on easily without a bunch of scanning and image posting that wouldn't help much.
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Henry



Joined: 09 May 2001
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Location: Allentown, Pennsylvania

PostPosted: Fri Jan 11, 2008 8:13 pm    Post subject: Reply with quote

Just my luck: I've got the Graftar 103, not the better Graflar 101. Makes sense, my Century is an early one (1954). One of these days I'm going to see what kind of enlargements I can get out of the Graftar.

Good to see that the Optar 101 came out OK.

Thanks again---waiting for more!
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Dan Fromm



Joined: 14 May 2001
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Location: New Jersey

PostPosted: Sun Jan 13, 2008 7:04 pm    Post subject: Reply with quote

TM, a practical question. Which target did you use?

I ask because your efforts have motivated me to think harder abut what I should do next. The best I can think to do, at least with 4" lenses, is to use a pair of Edmund's A83-001s, one for center and the other for a corner. As I calculate it they'll fit on a garage door. Comments?

Also, what film did you use? In the past I've used an ISO 100 E6 film because they're cheap and that's mainly what I shoot. For macro testing I've always use b/w, usually TMX. I think if I go with the 24" x 36" Edmund target I'll use TMX. Comments?
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troublemaker



Joined: 24 Nov 2003
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PostPosted: Mon Jan 14, 2008 8:05 pm    Post subject: Reply with quote

Dan,
Ugh!
OK, I used Acros as I have been able to develop it fine and sharp, and that's what I have. To be economical, but also because I have been using it for awhile, D-76 premixed liquid developer used 1:1.

The test chart I amusing was on the back of an old binder of Ed Romney's and is supposed to be the National Bureau of Standards chart.
Simply set up the lens at a distance 26 times the focal length and fire away.

Anyway, I ran into a problem. I am either getting focus shift when stopping down, or film curl. I've used three different backs. RH 10 appears to be the best. I have a Graflex 23 knobber that has the pin rollers and this is what I use use in the field. I tried to use a Graflex 22 that I thought was pretty good last night thinking I could get more lenses tests for center sharpness and the results were not useable as I could tell what the film recorded and what I saw on the GG were way off. I lighted and focussed much more carefully at f~8, then f~11 and looked really nice with a 10X loupe. I could actually see the bar lines down to about 34 lpmm. Then when I saw the two rolls of film I about gave up.
But my field tests came back really good?
Iwill try once more using the RH-10, carefully focussing again, and so forth. Even more lighting too.

Question, I had always thought focus wide and stop down to desired DOF. But is there a focus shift withsome lenses requiring muchmore careful GG work? Or am I seeing things?
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Dan Fromm



Joined: 14 May 2001
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Location: New Jersey

PostPosted: Mon Jan 14, 2008 8:20 pm    Post subject: Reply with quote

Ugh? That's not as good as I'd hoped.

Not that many lenses shift focus on stopping down. I've read repeatedly that Dagors do, but I have two Dagor types (not real Dagors from Goerz) and neither has that problem. If I were you I'd check the focusing panel; might need a fresnel and have none or have a fresnel and not need one.

FWIW, focusing on the GG has always been a struggle for me. I use an Ednalite Magnifinder (not a bad loupe and, I think, contemporary with the cameras) but sometimes miss with it. I have to be very careful, focus through "just right" from both directions a couple of times ... When I'm really really serious I use a 12x, which every one says is too high-powered to usable. Hmm. My GGs came from Dave Parker. What are you using?

When all I want to know about is central sharpness and the lens is long enough, I hang it in front of a Nikon. Cheaper and easier than shooting 2x3. Since I'm always curious about how lenses render color (short answer, I don't believe that any of my lenses except the radioactive ones that have yellowed has a color cast) I shoot E6, need exposure that's bang on. For that my old FG or newer N8008S (both will pick shutter speed for me given aperture) is ideal.

Oh, yeah, with lenses 6" or longer made to cover 4x5 or larger, all that matters on 2x3 is central sharpness. But with shorter lenses one has to check what's in 2x3's corners.

Keep at it, and sometimes this spring I'll trundle over to Edmund, buy the targets and have at 'em.
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troublemaker



Joined: 24 Nov 2003
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PostPosted: Tue Jan 15, 2008 2:29 am    Post subject: Reply with quote

I've got a bunch of roll backs. I load them with film and paper and check for fore and aft play or curl if you will. Last time I did this , a few weeks ago, I thought the RH-10 backs were pretty good. The Graflex 22 was not bad and is considered the best of the older knob winders, and I used this one a lot mounted with spring clips on my Mini-Speed hand held and get really nice images with a 127mm stopped only to f~8 or 11. The old Graflex 23 knobbers with no pin rollers are scarry, but I used those too with good results when it was all I had, and came away with some stunning stuff in color.
I took some lenses down to the harbor and did some near far images and had no problems using the pin roller full frame 23. I have the front standard flipped around on my backpacker Crown 23 and got some nice sharp stuff, also use the little bit of swing for tilt when Ihave the camera in the verticle. Everything came out supperb. Most impressive was the 65 Raptar image I put in the enlarger and it holds up to 40". I made the same shots with the 65 Angulon and at first thought I had my notes backwards. but had the same results on the second roll. I didn't see any noticeable light fall off in the upper corners with either lens, nor didthe bed appear on the bottom of the image as it will on a 4x5 with a 90mm. I did see that image sharpness at the side edges wasn't good, but this would not be an issue ifone things with slight cropping in mind.
So I figure if I can get the infamous little Raptar to perform that good, on the same camera, with the same GG and loupe, with ten degrees or more of fwd tilt, I should be able to shoot straight ahead from 66 inches at a test target. So I think it was the back that let me down. There are a couple things I intend to try. Acros is a pretty thin film, whereas Tmax films have a much thicker base. I am going to check the backs with both. I will also mount my test patterns on a board and take it outside in bright sunlight.
For GG, I do have a couple of Dave's installed on a couple cameras. But I find that they are a little more gritty than the originals and I like a good clean Graflex GG for fine work, esspecially stopped down. But, I will take a look this evening through my Speed with Dave's glass mounted. The GG panel I am using is a actually a filmplane panel from a broken roll back that I glued the GG right to the film plane. I noted a discrepency between the Graflex focussing panel and the actual film plane. But Ican do a couple tests with both. I got bunches of 'em. Another thing I will do is pick out a camera body with snugger rails, and tension the focussing pinion. I found some rail play shift on the body I was using.
So, what I will do next is a target resolution test with my Asahi 50mm 1.7 and 135 3.5 mounted on a K1000 as I know these to be high on the pretty good lens scale. This should at least tell me something about my methods. And though I would not want to do this a lot, I can shoot a sheet of 4x5 at the test target with one of the medium format lenses next time I load big film as I know that will be flat, and on the right plane. It may also give a good account of the coverage, which I wanted to try once to get a visual idea of available movements if Idecide I want to keep the fwd tilt standard set up.
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45PSS



Joined: 28 Sep 2001
Posts: 3201
Location: Mid Peninsula, Ca.

PostPosted: Tue Jan 15, 2008 5:00 am    Post subject: Reply with quote

The lens test targets downloadable from this site might be of use to you for your lens testing even though they were designed for digital camera lens testing. Print them on your printer. I made severa copies and positioned them on a 20x24 canvas and use that for RF calibration as well as lens test.

http://www.normankoren.com/Tutorials/MTF5.html
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troublemaker



Joined: 24 Nov 2003
Posts: 715
Location: So Cal

PostPosted: Tue Jan 15, 2008 6:08 am    Post subject: Reply with quote

Some interesting stuff and ideas there that will help thanks.

OK, I made some progress. I didn't have any thicker base films in fine grain so went with TMY and a reliable RH-10 back, and ran a quick one roll test with an assortment of lenses just to see if I could get useable results. I added two more photo-floods to aid focussing. Tmax 400 grain makes judging resolution scores difficult beyond 48 lpmm, but I could distinguish lines in some cases.
I ran the lenses I'm most curious about, but will attend to a better comparison test when I get some TMX and can spend the time to do what I originally set out to do.
I shot only the first lens at f~16 and then f~22
All others are f~22.

Quick test results are as follows:
101mm Optar:
f~16 48 lpmm clearly, 56 lpmm barley distinguishable.
f~22 40 lpmm clearly, 48 lpmm doubtful

101mm Ektar (coated)
f~22 40 lpmm clearly, 48 lpmm barely

105mm Ektar (uncoated)
f~22 40 lpmm clearly, 48 lpmm barely

105mm Xenar
f~22 48 lpmm clearly, 56 lpmm barely

103mm Trioptar
f~22 48 lpmm clearly, 56 lpmm barely (slightly better than Xenar)

101mm Graflar
f~22 48 lpmm, 56 lpmm doubtful

135mm Xenar
f~22 48 lpmm clearly, 56 barely (slightly better than 135 Optar)

135mm Optar (early production)
f~22 48 lpmm clearly, 56 lpmm maybe

8" Tele-Raptar
f~22 40 lpmm clearly, 48 lpmm maybe

Comments:
I mounted my best Nikkor 2.8 EL lens and enlarged to what would be approximately 48" print size. Big. The best of the bunch is the junky little Trioptar. I've used it on many trips, and have made some fine images with it. Mostly color. Ektars I rarely seem to use. But one reason I am testing them is see if they are any better than what has been going in the bag. I use the Trioptar mainly because it is lighter and has proved to be a good performer for backpacking. I thought the Graflar would be better than it tested. It is a contrasty lens however, and certainly worth trying out. I was impressed with it when I first tried it last year. For fine detailed prints with sharp contrast the Xenar 105 is an excellent performer. I was actually surprized the Trioptar was slightly better in resolution. I shoot the 101 Optar around town. It lives on a beautiful Crown 23.
I also like to use 127 and 135mm lenses on my 2x3 cameras so will be taking a look at some of those. I added the 8" Tele-Raptar out of curiosity. Certainly turned in a higher resolution than I expected. It makes a wierd glowy image. I've never been able to make up my mind about it. I'm going to set it up for uncoupled RF hand holding and try a couple portraits with it. Slight edge separation in the rear cell common to these, but otherwise spotless.

Next I'll approach this with more care, time, and TMX 100 film and give each lens a fair chance at a wider range of apertures.
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clnfrd



Joined: 26 Mar 2002
Posts: 616
Location: Western Kentucky Lakes Area

PostPosted: Thu Feb 21, 2008 8:14 pm    Post subject: Reply with quote

Troublemaker, please check your PM's. Fred.
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