Possibly a result of front element being backwords?

[richterjw]

<p>I recently did work on my Agfa Billy Record, cleaning the individual lens elements. The attached photographs show a sharp center with distorted peripheries. Could this be the result of my having inserted the front element backwards? Any other possibilities? Thanks. JR</p><div></div>

[richterjw]

<p>shot on Ilford HP5+</p><div></div>

[richterjw]

<p>This one is prior to the "restoration."</p><div></div>

[John Seaman]

<p>What lens has it got? I did a similar job on my prewar version with Apotar lens, and it's difficult to see how you could reverse the front element - it has a strong convex curve facing forwards, ditto the rear element, the more protruding convex side should face backwards, towards the film, although mine stayed in its metal cell anyway.<br>

Looking at your pictures, the problem seems worst to the left hand side of the bridge shot, whilst the bottom of the railway lines shot seems quite sharp. Could there be a problem with the lens not being parallel to the film plane? To check mine I laid the open camera on its back on a level surface, and used a spirit level to check the levelness of the lens. It turned out the lens was not parallel, causing one side of the image to be out of focus - a little judicious bending was needed to fix it.</p>

[LenMarriott]

<p>Jeremy, " Lens" is a German word which translates roughly to the French word "carburetor", which again, translated into English, means "Leave it alone!". Good luck on your 'restoration'. Post photos when you get it right. :-) Best, LM.</p>

[bueh]

<p>Could also be a reversed rear element...</p>

[JDMvW]

<p>Len has a point. As the little Scotsman in the old horror films always says</p>

<blockquote>

<p>They'rre thins man isnae meant to ken.</p>

</blockquote>

<p>However, the results above certainly look a lot like what has resulted from Gene M. and others' reversed lens element (somewhere) on box cameras.<br>

You can either try to fix it by trying lenses the other way around, you've got a 50% chance of getting it right with each element, unless elements have been inadvertently swapped.</p>

<p>or, you can accept this as a sort of Petzval (e.g., <a href="http://www.flickr.com/groups/868027@N25/">link</a>) effect and use the camera for portraiture. :)</p>

[alex_lofquist]

<p>This looks like the image I obtained when I accidentally reversed a doublet (acromat) group in a projection lens. It wasn't obvious just looking at it. What type of construction does the Billy lens have?</p>

[mfophotos]

<p>Some people go to great lengths to achieve the same effect! </p>

[richterjw]

<p>It's definitely not the rear element. It appears the front element may be a little loose, which (as suggested) would account for the differences in the effect between the two frames.</p>

<p>Re Alex: It's a 3-element lens (105mm f/7.7).</p>

<p>Re Len: I've always had success with carburetors. JR</p>

[ridinhome]

<p>Sell it to a hipster as a retro Lomo, you'll make a fortune.</p>

[Rob_the_waste]

<p>The first picture kinda looks like what came from a Domiplan that I had (and gave up on).</p>

[andylynn]

<p>If the bridge photo is reproducible, I want one!</p>

[jodys]

<p>With triplet lenses, the most common mistake is in fact to put the <strong>center </strong>element in backwards, and that does result in the effect you've shown. It's the poor man's 'Petzval' or 'soft-focus' effect (before there was a 'Lomo' effect).</p>

[tom_mann1]

<p>The previous posters advice is right on the mark, so I won't comment further. However, I found it ironic that this thread appeared just to the left of an advertisement for LensBaby products.</p>

<p>;-)</p>

<p>Tom M</p>

[leigh_marrin]

Jeremy, here's a thread from Large Format Forum that might help. One of the posters had a mis-assembled three-element

projection lens and got results fairly similar to yours. Another person then showed the correct element position for a Cooke

triplet. See: http://www.largeformatphotography.info/forum/showthread.php?t=63183

[chuck_foreman1]

I had this experience my self and I was ne3ver satisfied with an answer for the cause. Some of the suggestions here make sense. One poster noted though that it's almost impossible to mount the front lens backwards, and if I understood correctly the middle lens wasn't removed so how could it be backwards. Another poster mentioned the lack of parallel and while that seems plausible depth of filed would compensate somewhat and the light unsharp edge would be evidence of this problem.

Most plausible is reference to the middle lens.. but how can it be backwards if it never was removed? In my case the shutter leaves on my Yashica D were beginning to stick and I'd have to pay 50,00 dollars every time I used the camera. It was Ok as long as you used it, but let it sit a week or two it would stick. After I realized I could spin off the front element and merely touching the leaves with a swab was enough to free it up for a roll, it was Ok. Then after 3 or 4 rolls suddenly the effect we are describing here. After explaining the problem to the repair man, He said for 50,00 dollars they would replace the shutter. However, after I got it back it wasn't collimated or not correctly. The results were all out of focus. Now in Germany, the new repairman wrote "damaged" and implied the repair was beyond the value. Years later I sent it to Mark Hama and he replaced the whole lens so I still don't know what caused the problem. Like you I didn't remove the middle lens, so that can't be it. My theory is that the threads are stripped and therefore the distance to the middle lens is either too close or too far away. I'd love to have a proper explanation.<div></div>

[richterjw]

<p>Update: I tightened up the threaded metal part that holds the front element in place. The element appears to be more tightly held in place now, though there is still some wiggle room. I don't know if that was always the case, even before my tampering; we are talking about an 80-year-old device. I suppose we'll see in a few months, when I finish this roll of film and eventually develop it. Thanks for all the ideas and even the encouragement to use it in its current defunct state. JR</p>