What to expect from a pre-war Voigtländer 10.5cm/3.5 Skopar lens?

Loris Medici · Oct 19, 2010

Hi all,

I purchased a pre-war Bessa RF (E-messer) 6x9 - in a very good condition cosmetically and mechanically - a couple of months ago and I also had it CLA'd by a proficient technician.

After some practical field tests, I found it doesn't give me enough sharpness and resolution. I would guess the resolution is around 20-25 lp/mm; a magnitude less then what I was expecting. (I was expecting at least 40-45 lp/mm or better - at F16, on a tripod in calm weather, using a cable release...)

Am I daydreaming? Am I expecting too much?

What are your results with similar equipment?

Thanks in advance,
Loris.

R gould · Oct 19, 2010

don't mesure lpm or such, I look at the negatives, and I have a 1938 bessa 66, the baby bessa, with a viogtar lens, stopped down to 11 or 16 it is sharp, reasonable contrast and just nice photographs, you can't compare these old lenses to a modern lens,Mine is a triplet, these are uncoated lenses ans are of their time, What lens have you got,is it the Skoper,which is one of the best lens of its type? My advice is not to worry about resolving power, but just to enjoy using a 70+ year old camera and don't expect to get the same results as you would get from 50 year old lens, they were simpler times, and as long as you got a good photograph that is all that was asked, and that is all you can ask,Richard

Loris Medici · Oct 19, 2010

R gould,

I have a Yashica 124G which has a severely fungus infected taking lens that performs better than this particular Skopar when stopped down to F11 and above... My the question is to learn if I have a lemon (or maladjusted sample) on hands or not, therefore asking for your experience. The question isn't "Can I take beautiful photographs with this camera?" at all! I can do that (err, did - and continue to do...) with a pinhole camera when appropriate... Anyway, thanks for the feedback even if it wasn't exactly what I was looking for.

Regards,
Loris.

domaz · Oct 19, 2010

Almost all the old folders suffered from bad film flatness. To really test this lens you need to take it off the old folder and put it on a decent 2x3 or 4x5 camera.

Loris Medici · Oct 19, 2010

domaz, not an option; I'm interested in the performance of the whole system - actually. Sorry, it wasn't clear in my original post...

OTOH, I have wound the film right before taking the shots; that should have taken care of the possibility of film sagging, no?

Thanks,
Loris.

domaz · Oct 19, 2010

You need to design a whole new pressure plate I think to really make it better. Take a look at Chris Perez's MF lens test- he doesn't list your particular camera but he tests one pretty similar (Zeiss Super Ikonta C, another 6x9) and it to gets <20 lpm.

Loris Medici · Oct 19, 2010

See, see... That was helpful indeed. It seems I was expecting too much from this system, in fact!

Leaving bitching mode and switching on shooting mode back now!

Thanks & regards,
Loris.

ntenny · Oct 19, 2010

domaz said:
You need to design a whole new pressure plate I think to really make it better. Take a look at Chris Perez's MF lens test- he doesn't list your particular camera but he tests one pretty similar (Zeiss Super Ikonta C, another 6x9) and it to gets <20 lpm.

That page confuses me---the camera says "Zeiss Super Ikonta C", but the manufacturer says "Muscova" and there's no lens name (I think all Zeiss cameras would have identified the lens by name). Did he test a "real" Super Ikonta or a Moskva-5? He also has a note at the bottom that the rangefinder may have been off.

Looking at the last line in the same table, I would be really surprised if a Skopar (which is a Tessar type) couldn't outperform the Vaskar triplet, even allowing for the format difference! I haven't done my own lpmm tests, but based on those test results and my eye's experience of Skopars vs. triplets, I would at least look at other possible sources of trouble like the rangefinder before giving up.

-NT

Ian Grant · Oct 20, 2010

I think you'll find Chris Perez tested a Russian KMZ Moskva, they made a series of Super Ikonta copies, the Soviets took equipment & tooling from the Zeiss factories at the end of WWII. It's possible the camera Chris tested had the Cyrillic rather than Latin lettering.

It may be you were unlucky with this lens Loris, some don't seem to age well. I have a Ikonta with a Novar and it's a terrible lens soft in terms of sharpness & low contrast yet it looks very clean, it's only a triplet design but usually they are quite good performers. I had a Triotar (again a Triplet) on an early Rollei and that was a good sharp lens once stopped down. It's a bit hit and miss with some 1930's lenses.

Ian

Loris Medici · Oct 20, 2010

See visuals below

Ok, maybe it's better to provide few visuals. See below:

1. Screen version of full frame scan:

2. 100% crop of scan:

It's the first time my beloved Epson Perfection 2450 "outresolves" a negative...

EDIT: BTW, looking to the 100% crop "in my screen" is the equivalent of sniffing a print sized 37 x 55 1/2" (~ 94 x 141cm), actually... Maybe the lens / system isn't bad at all! Probably I was - somehow - being in a state of delirium, yesterday...!???

polka · Oct 24, 2010

I too think that 25 lp/mm with a 6x9 folder is not bad at all : put that down to 24x36 and you get 60 lp/mm, which is fair ? maybe not absolutely !? but for a prewar folder with a relatively simple lens not coated, I would be satisfied.

However, maybe it's not only because of the lens. You should test it at all apertures (on the same landscape) and compare the pictures to see if you get decreasing resolution proportional to the aperture or better.

If you get decreasing resolution proportional to the aperture, then maybe it's not the lens but the mechanical adjustment of the distance to the film (cercles of confusion are proportional to aperture).

In any case, you should also check with a shoot "full open" if you get the same resolution everywhere, and if not, compare the resolution where it is best to resolution away of this spot. If you get resolution decrease proportional to the distance to max. resolution spot, then maybe you have also a slight misadjustment of the parallelism of the lens to the film plane.

You see that you might check for a lot of defaults before incriminating the lens. Anyway, your folder should come clean if you see not a lot worse than what you saw at F16, at full aperture. And don't forget that most of the amateur prints in those times were "contacts". It's only with the very good cameras that we have today that we demand huge and however precise enlargments

Paul

P.S. I had a Kinax (french folder) that gave me approx. the same results than yours at F16 but could not be used under that aperture, because grossly machanically misadjusted. As it used 620, I did not bother to repair it, and put it simply on the show-shelf

Loris Medici · Oct 25, 2010

I have a better (processed) sample below:

1. Screen reproduction of full frame scan (800x533px)

2. 100% crop of 1600spi Epson 2450 scan

(The leftmost youngster's width at 12x18" / 30x45cm print size would be 0.1" / 2.5mm)

(TMY2 souped in Pyrocat-MC. Shot hand-held...)

I'm generally happy with the camera now. Its only problem is the uncoated lens elements; I get some unwanted reflections / ghost images in extremely high contrast areas, when lighting conditions are difficult / extreme. I guess I'll have to improvise a lens hood and carefully select subjects in order to avoid this... BTW, after careful checking, I couldn't find any front standard parallelism or pressure plate problems in the camera.

Regards,
Loris.

Loris Medici · Oct 25, 2010

polka said:
...
P.S. I had a Kinax (french folder) that gave me approx. the same results than yours at F16 but could not be used under that aperture, because grossly machanically misadjusted. As it used 620, I did not bother to repair it, and put it simply on the show-shelf

My local technician was talking about this brand, telling me how so good were those cameras and their lenses. Probably it was a newer model that uses 120, though...

Regards,
Loris.

EDIT: Hmmm, according to this page, none of the Kinax cameras were using 120 film. Anyway...

Alan Johnson · Oct 25, 2010

The Bessa 11 was tested in Amateur Photographer Mar 19 1952 .At f/16 the best on axis resolution was 48 lppm.edge 25 lppm.The test was done with HP3 film which limited the maximum resolution to 55 lppm.
If you are using modern slow speed film for a resolution test higher values would be expected.The test is best done with the focus also set a little more and less than the indicated distance.

elekm · Oct 26, 2010

I was going to ask whether infinity focus had been set correctly on the lens. The Skopar is a Tessar-type with four elements.

The Tessars that I've used from roughly the same time period have been extremely sharp.

I have a writeup of a Zeiss Ikon Ikonta 6x9 here.

Erik Petersson · Oct 27, 2010

Mike Elek, I am impressed by the sharpness you get. I also have a "E-messer" 6x9, but not getting as sharp pictures as I was hoping for. I should probably try it again with
- tripod
- high aperture (f11 or so?)
- try to keep the film stretched

By the way, how can focusing be checked? Is there anything else I can do to improve results?

Loris Medici · Oct 27, 2010

The lens was collimated and the rangefinder was adjusted by a proficient technician. (Infinity focus and RF is spot on...)

After some practice and getting used to it, I'm quite happy with the camera - except the fact that I experience occasional problems (flare & ghost images, specifically...) with the uncoated optics, in extreme backlighting situations. I'll improvise a lens hood and select subject matter carefully... I may upgrade to a post-war Heliar mode later!

See a couple of examples from my latest shooting session below:

1.1. Full frame, screen size repro:

1.2. 100% crop of 1600spi scan:

2.1. Full frame, screen size repro:

2.2. 100% crop of 1600spi scan:

- 100% crop images were post processed / optimized for 12x18" (30x45cm) print size.

- TMY2 in Pyrocat-MC

- Epson Perfection 2450

Regards,
Loris.

polka · Oct 27, 2010

Not bad, finally ? I think "prewar" folders are a must : such big negs... so easy to carry (in a =large= pocket)... the thrill to have to guess all settings... the focus of (amused) attention you get when shooting...

and such precise pictures !!!

Paul

Erik Petersson · Oct 27, 2010

I will post an example of the low quality I have achieved, as soon as I can. Do you find that the resolution improves much on higher apertures?

sanking · Oct 27, 2010

Loris,

Did you make the test with the camera hand held or on a tripod?

If hand held I think 25 lp/mm is excellent for a camera of this type.

I owned for a while a Bessa II. On a tripod it was capable of 50 lp/mm at f/11. Remember, the lens on this camera is fairly long so any shake or lack of absolute focus is going to reduce resolution.

Sandy

Loris Medici · Oct 27, 2010

Hi Sandy, the "guys in the roof" (detail) image was shot handheld at 1/100. The last two shown above were shot on a tripod, using a shutter release cable. (But 1/2 - 1/5 shutter speeds this time...) All at F16 - F22.

Regards,
Loris.

Removed Account2 · Oct 27, 2010

+To me the samples here look bitingly sharp.

One should not go overboard with crops, that is looked upon at close range (screen).

Keep in mind a few simple facts : 1 meter and above enlargements are expected and designed to be looked upon at a WALL.

also looking at a picture, you dont see the performance of the LENS, you see the performance of a system :

Film, focus, lens, scanner/enlarging lens, limits from screen or photograpic paper, just to mention the obvious.

Each element in this equation contributes to the overall performance.

Film performance is usually overrated from the manufacturer, stating what can be achieved in a lab, under perfect conditioons, perfect development and perfect exposure. Normal perfoirmance is from 40 lpm to about 80, while the manufacturer quotes double of that.

The equation is for a simple system something like this, (lens, film, enlarger) :

1/100 + 1/60 + 1/100 = 6/600 + 10/600 + 6/600 = 22/600 = 2,2/60 or approximately 1/30

The lens performs flawlessly at 1/100, the systems yelds 1/30, which is good.

Similar calculation can be done for any system, and can be likened to serial connected resistance in a electrical cirquit. Think of it as total resistance of image quality.

I think you originally trapped yopurself into too high expectations and have now sobered up, this is a nice camera, and if you're disappointed I will take it off your hands in a second and be happy!

Erik

polka · Oct 27, 2010

Erik,

Your camera is generally considered a very good one, so even fully open you should get sharp pictures when well focused. So, try landscapes : with everything far away, with distance set on infinity, you cannot have DOF issues. So if the pictures are unsharp, some mechanical adjustment may be wrong.

here I wrote a paper on "adjusting and using folders" (however in french), this could help ?

Paul

Oops, there are two Eriks here, this post was meant for Erik Petersson

bblhed · Oct 27, 2010

I love small folders, and I have a thing for ones from the late 20's and 30's and also post war. One thing I love about these cameras is that they can deliver great results, but in the end while they have a bunch of settings on them they are still point and shoot cameras and should be regarded as such. I'm not saying you can't get fine art or lovely portraits out of these cameras, the photos I have on display that I took of my children were taken with a Kodak Brownie Autographic #2 folding camera, I'm just saying that you can never be 100% sure of the results you will get.

Like Erik above, I would be happy to provide a good home for this camera as well.

Loris Medici · Oct 27, 2010

The camera has a good home already!...

BTW, I just ordered a 37mm standard metal lens hood. Maybe I will have problems mounting it to the non-standard front thread, I don't know - it was cheap enough...

- What is the exact size of the lens filter / hood thread of the Bessa folders?
- What are the good sources for Bessa lens hoods?

TIA,
Loris.

What to expect from a pre-war Voigtländer 10.5cm/3.5 Skopar lens?

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