Testing wide angle converters on 6x9

[iangreenhalgh1]

Wide angle lenses for 6x9 are both hard to find and expensive. Therefore I thought of trying some add-on wide angle converters. Not the common, cheap 2 element ones that can be reversed for macro, those are crappy. I bought a very nice Schneider-Kreuznach 4 element 0.7x one, (amusingly labelled Xenar) and on my 24 and 28mm Konica Hexanons it doesn't reduce the sharpness or contrast at all, doesn't introduce CA and doesn't increase distortion, IQ is rather impressive.

http://forum.mflenses.com/viewtopic.php?t=57355



So I thought I'd try this one on 6x9. I mounted it on my Mamiya-Sekor 2.8/80 using a 55-40.5mm stepping ring. I used Kodak Industrex MX125 x-ray film rated at ISO 12, exposure was 1 sec at f16. Developed in stock Kodak DK-50.

Without converter (sadly the shutter turns out to be running slow so it was over exposed, spoiling the tonality and causing that blown highlight on the road):



With converter, exposure was closer to ideal:



The FOV is now equivalent to a 24mm lens on 35mm and the converter hasn't added any visible distortion or vignetting. I could see a reduction in sharpness on the ground glass however, which surprised me as the converter hadn't reduced sharpness when I tried it on my NEX.

100% crops don't show much difference in sharpness, this is due to the Industrex film which is double-sided so is less sharp than a single-sided film such as FP4.

Without converter:



With converter:



Hmm, not sure what to conclude, I shall have to repeat the test in better light with a 'normal' film. I also have a 4 element Century 0.65x converter to try and a 3 element Raynox 0.3x semi-fisheye converter that might be fun.

[Attila]

It was worth to try and result is not too bad!

[iangreenhalgh1]

Yes, not terrible, but not as good as I hoped. I will try it with a different lens such as my Schneider Componon-S 5.6/100.

[dan_]

A Happy New Year!
Having better coverage the Componon may behave better with the focal reducer. I'm curios to see your results, too.
The little Schneider-Kreuznach 0.7x looks like a very capable focal reducer.
Have you tried it with lenses in the 100-150mm range on APS-C?
If it's as good as with wide lenses I'm interested in getting one for some of my experiments.

[kryss]

Happy New Year Ian,I am not sure why you used a 55mm-40.5mm step down,the WA has 55mm thread so does your Mamiya lens have 40.5 mm thread ? I have a Feinmess Bonotar redV 105mm f4.5 which is 40.5mm the only lens I own with this filter size out of 200 + lenses I have.

[iangreenhalgh1]

Happy new year guys!

Hi Dan, I haven't tried it, but I will do if you like, I can put it on one of my Konica 135mms as those have 55mm threads. These converters are fairly common on ebay and often sell for next to nothing, I think they are well worth having.

Hi kryss, yes, the Mamiya has 40.5mm threads. i have lots of lenses that do, the Componon-S 5.6/100 does, as do most Russian rf lenses - I-61, I-22, J-8, J11, J12 etc. My Sonnar 1.5/50 does too.

[kryss]

Ah,thanks for info,I do not own any RF lenses and methinks I should not,enough LBA syndrome as it is.

[dan_]

Ian, you'll be very helpful if you could post in one of these days a couple of samples taken with the 135mm Konica with and without the focal reducer to see if the resolution degrades with the focal reducer and how much increases the CA in the corners.

[iangreenhalgh1]

Hi Dan

Sorry, I completely forgot about this thread. Next opportunity when it isn't raining I shall try that for you.

The weather here has been abysmal for photography, just so dull and gray and incessant rain.

I bought a pre-war Agfa Isolette that was just a total mess, rusted, bellows in pieces, junk. But it did have a Compur Rapid #00 shutter that looked okay. The Apotar 85mm lens was full of fungus so I threw that away with the rest of the camera and just kept the shutter. After giving it a thorough flush and clean with lighter fluid and relubing it with 3-inone oil, it runs like clockwork. I had a Schneider Componon 5.6/80 sitting around and the cells fit a #00 shutter. Schneider rate this lens for 6x6 enlarging but they are known to be very conservative when stating the coverage of their lenses. Anyways, I made a lensboard and mounted this Componon/Compur combo for my Century Graphic and tried it out. Sadly the paper negatives I shot were ruined by heaving fogging but it was clear the lens fully covered the 56x80mm frame. No room for movements, the image circle appears to be 100-102mm and the diagonal of the frame is 98mm so it's tight but it covers and there doesn't appear to be any noticeable falloff of illumination or falloff of sharpness so it will work fine as a moderate wide angle if movements are not needed.

However, I already have two other 80mm lenses for the Century so my reason for wanting to try this Componon 5.6/80 is that, being an enlarger lens with a flat field, it might be a good base to use with a wide angle converter. I happened to have a Sony VCL0637 0.6x converter, a small 3 elements in 3 groups item with 37mm threads, but it came with half a dozen stepper rings and one of them fits the Componon. The 80mm + 0.6x converter combo gives me the FOV of a 48mm lens which is petty wide on 6x9, equivalent to a 21mm lens on the 35mm format.

I made a couple of test exposures to see how this combo works, but sadly, the 1968 expired Kodak Panatomic-X I used has heavy base fog due to age so I need to repeat the test with better film. However, this shot shows promise as I don't see much distortion at all or falloff of illumination or sharpness.

[buerokratiehasser]

Methinks Ian needed to get closer with the UWW, step some 5..10 metres forward for sample 2.

[iangreenhalgh1]

Hello, do you mean the picture of the railway and I should have moved to the other side of the bridge?

I framed the bridge in the shot just to see what the distortion would be like, but i agree, it's not a very good composition.

[buerokratiehasser]

Of course, these are test images, and framing is always matter of taste
Scrolling down from sample #1 to sample #2 gives the impression that it's the same just "more (angle) of it". Illustrating the smaller focal length nicely but..

Just saying - not bickering.
Rockwell says get closer. Get closer with your UWW. "Closer!"
And I am inclined to say he is right on that one.
Of course, not so good for technical comparison, focal lengths and sharpness check.

[iangreenhalgh1]

Yes, good point. I chose the composition because I thought it would reveal distortion if the converter added any and would also show the difference in fov easily, I didn't consider the aesthetics.

[iangreenhalgh1]

I made a mistake, that image of the railway station is actually without the converter, just the Componon 5.6/80 on it's own.

I've had two attempts at using the 0.6x converter with this Componon and both times the results were very soft, but I am not convinced it isn't user error so I will keep trying. I also tried the Raynox 0.3x converter twice and both times the results were very soft indeed so I;m wondering if the spacing of the converter to the front of the lens is critical, I shall have to experiment.

Here's another shot with the Componon 5.6/8o alone, shows it has very little distortion. I also shot this scene with the 0.6x and 0.3x converters and the results were very soft so I will try again:



Kodak Industrex MX125 x-ray film developed in Fomadon LQN. Horrible foggy, rainy day. 1 sec at f16, ISO 12.

[iangreenhalgh1]

Well, after the third attempt with the Sony VCL0637 0.6x converter I can rule out human error and conclude that this converter produces atrocious quality results. The sharpness is reduced everywhere, but outside a small central area there is a pulling/zooming effect as well, just horrible.

First, without the converter, Componon 5.6/80, Kodak Industrex MX125 developed in stock Kodak DK-50. 1 sec at f16, ISO 12:
(Take note of the lack of any anti-halation layer on this film, hence the diffuse glow in the upper half of the frame.)



Second, with the converter. Aaargh my eyes, my eyes.....