fidget
Lemon magnet
My first test roll in my "new-to-me" Ikonta 521 with Novar lens showed no light leaks or other scary nasties. Some promising images were on there, but including one which seemed to show a focus change across the frame (in the plane of the lens door hinge. Still, only one poor image on the roll, it could be some other user error!?
So another test roll was loaded, this time shot to check for focus changes across the frame.
Here's one of several I took of a stone wall.
My fears confirmed. I just don't know the best way to deal with a lens board which ain't in the right plane. Usually haunts me on 6x9, I thought that I was on safe ground with a 4.5x6.
This particular Ikonta is in spectacular condition, all very solid. I'd bet it's in such good condition because.....it's never been used much, because it's had this fault from new.
How best to level the lens board then?
Disappointed Dave
So another test roll was loaded, this time shot to check for focus changes across the frame.
Here's one of several I took of a stone wall.
My fears confirmed. I just don't know the best way to deal with a lens board which ain't in the right plane. Usually haunts me on 6x9, I thought that I was on safe ground with a 4.5x6.
This particular Ikonta is in spectacular condition, all very solid. I'd bet it's in such good condition because.....it's never been used much, because it's had this fault from new.
How best to level the lens board then?
Disappointed Dave
hanskerensky
Well-known
Strange that the image almost jumps from sharp to unsharp. You would expect a more gradual decrease when the lensboard is not parallel to the filmplane.
You wrote that's a 6x4,5 so sucking the film partly into the filmframe by opening the bellows too quickly could hardly be an issue (it is sometimes with 6x9).
Wonder if there could be something wrong with the lens ?
Which lens is on the Ikonta and at which aperture you made this image ?
You wrote that's a 6x4,5 so sucking the film partly into the filmframe by opening the bellows too quickly could hardly be an issue (it is sometimes with 6x9).
Wonder if there could be something wrong with the lens ?
Which lens is on the Ikonta and at which aperture you made this image ?
FallisPhoto
Veteran
The transition from sharp to unsharp seems too quick, as the previous poster said. I'd be looking for lens fungus or haze.
fidget
Lemon magnet
Thanks for that, interesting possibilities.
This was shot at f5.6. Several shots of the same wall with varying camera orientations show the same problem. The camera was erected for all these shots, so film movement due to sucking it off the back can be discounted, at least for those after the first. The scale distance was set to 15ft.
Notice the row of houses just peeping over the wall on the right? They are fairly well in focus, the left side at infinity being less so, suggesting a focus shift rather than something fuzzing up part of the image. Maybe not so much haze or fungus?
Just to add to my confusion, I took a shot of a brick wall on the same roll and day. Also at f5.6 but at 5ft. All seems fairly well in focus? I thought that perhaps there was some change in the way in which the lens was erected.
The orientation is different here, I expected there to be a focus shift from the top to the bottom. The top of the frame corresponds to the right of the wall in the first image.
This was shot at f5.6. Several shots of the same wall with varying camera orientations show the same problem. The camera was erected for all these shots, so film movement due to sucking it off the back can be discounted, at least for those after the first. The scale distance was set to 15ft.
Notice the row of houses just peeping over the wall on the right? They are fairly well in focus, the left side at infinity being less so, suggesting a focus shift rather than something fuzzing up part of the image. Maybe not so much haze or fungus?
Just to add to my confusion, I took a shot of a brick wall on the same roll and day. Also at f5.6 but at 5ft. All seems fairly well in focus? I thought that perhaps there was some change in the way in which the lens was erected.
The orientation is different here, I expected there to be a focus shift from the top to the bottom. The top of the frame corresponds to the right of the wall in the first image.
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hanskerensky
Well-known
Just wondered, because until now i (luckily) never had experience with such cases, what would be the effect of one of the lens elements being accidently reversed, glasses from a kitted element separated or even a loose (so shifting) element.
fidget
Lemon magnet
A lose element is one of the more unpleasant possibilities. A reversed element might be expected to give a symmetrical effect, I think? All welcome ideas. I will next set up the camera and measure the amount of run-out of the lens objective element to the film plane. (I got a lot of practice at this with my two Moskva 5s)
I've spent a short while this evening with a ground glass screen fixed to the film plane, looking at a brightly lit close target. I detect a significant difference in sharpness across the frame.
Dave..
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FallisPhoto
Veteran
Why would a loose element be an unpleasant possibility? It is one of the easiest repairs. A reversed lens tends to give a tunnel-vison sort of effect, with some lenses, and you lose the ability to focus at infinity with others, so I doubt that's it. Still looks to me like something was on the lens. Maybe there was some fogging on the first photo?
fidget
Lemon magnet
My initial thoughts about a loose element were that some critical part which locks the element in place (packing shim, threaded ring etc) might be missing, and so be more difficult to find a part.
hans voralberg
Veteran
Screw open the lens and find out? I think most folder lens are fairly simple in construction so you might not have much trouble figuring out what's wrong
FallisPhoto
Veteran
Zeiss Ikontas, and nettars, don't have shims around the lens elements. It might be that you just need to tighten a ring. Incidentally, I happen to have a spare Nettar Novar lens/shutter, and I'll be back home in a couple of days -- want it?
Proteus617
Established
Not to compare the two, but I have a Moskva5 that has a very similar erecting mechanism. Very small alignment issues with the arms can prevent one or both of pins on either side of the standard from seating correctly. You may just have to double check that both pins have "clicked in" whenever you open it?
hanskerensky
Well-known
That's true, i also have a Moskva 5 which was well used in its lifetime and suffered from this notorious weakpoint. But it should be very easy to see and feel if that's the case with the Ikonta. Before repair of the Mockba i could wobble the whole lensboard in all directions.
fidget
Lemon magnet
Thanks all for your ideas and thanks FallisPhoto for your kind offer. I should at least check the lens board alignment and even dismantle the lens assy (it needs a clean/flush to free up the slow speeds anyway) before I replace the shutter/lens.
I had an arrangement where I rested the cam (Moskva) on it's film guide rollers onto a straight edge and placed another straight edge (2ft steel rule) across the lens bezel. This will give me an idea of how much the lens assy/board is out of true by.
On the Moskvas I did not need such an arrangement to check if they were out, that was obvious. It was needed to check that my shimming of the lens assy brought it back to an acceptable figure.
I'll post a picture of my lash-up when I have time.
Dave
FallisPhoto
Veteran
I was thinking it might be something as simple as the user having inadvertently breathed on the lens and partially fogged it -- it happens. Don't ask :bang:
hans voralberg
Veteran
Hehe yeah that just happen to me two days ago actually, luckily it was on a TLR. I looked through the finder and it was WTF? then I realize I walk into the house from a freezing cold day so water condensed on the lens.
dave61
Established
This is one of the great (?!) things about 120 folding cams LOL. They bring us back to our roots in photography's primitive early beginnings, when something could (and almost always did) go wrong.
Keeps things interesting, eh?:bang:
Seriously: What about the film? Is it thin-based film on thin backing paper? Ilford seems to suffer from this more than Kodak and Fuji. Film that's curved across film plane could do this. Some films sit flatter than others, too. Weak pressure plate spings make it worse. Check pressure plate alignment for lack of even pressure.
We'd think flatness shouldn't cause trouble with 16-on-120, but: If temperature + humidity change are enough to cause condensation, this will influence film flatness. Film base reacts to temp + humidity, expanding and shrinking. Some films, like Kodak Professional films with Estar base (li.e. PXP 120) use special, thick base stock to minimize this. Add to this backing paper not shrinking /expanding at same rate. Slack/uneven film flatness develops.
Kodak used to recommend letting their 120 film 'aclimate' for something like an hour (?) for every 30 (?) degrees (farenheit) change (if I remember correct) when going from one temp extreme to another. Stands to reason that camera, lens, shutter and film all need to be at same temp and suited for cold weather use (congealing shutter and RF lubricants, anyone?) The tropics also require special considerations, as anyone who's travelled extensively with vintage cameras can attest.
Keeps things interesting, eh?:bang:
Seriously: What about the film? Is it thin-based film on thin backing paper? Ilford seems to suffer from this more than Kodak and Fuji. Film that's curved across film plane could do this. Some films sit flatter than others, too. Weak pressure plate spings make it worse. Check pressure plate alignment for lack of even pressure.
We'd think flatness shouldn't cause trouble with 16-on-120, but: If temperature + humidity change are enough to cause condensation, this will influence film flatness. Film base reacts to temp + humidity, expanding and shrinking. Some films, like Kodak Professional films with Estar base (li.e. PXP 120) use special, thick base stock to minimize this. Add to this backing paper not shrinking /expanding at same rate. Slack/uneven film flatness develops.
Kodak used to recommend letting their 120 film 'aclimate' for something like an hour (?) for every 30 (?) degrees (farenheit) change (if I remember correct) when going from one temp extreme to another. Stands to reason that camera, lens, shutter and film all need to be at same temp and suited for cold weather use (congealing shutter and RF lubricants, anyone?) The tropics also require special considerations, as anyone who's travelled extensively with vintage cameras can attest.
fidget
Lemon magnet
Thanks for these suggestions.
I was concerned about film flatness. I checked that the film wasn't buckling across the film gate due to the reel being too tight on its springs. I loaded a test film and wound, opening the back now and then to peek at the film across the gate, looking for a buckled film, none found.
I've not got round to dismantling it yet, too many other projects and my 6x6 folding Kershaw 450 is producing some gorgeous images at the moment, so this cam is not urgently required.
I have a new theory. When I look into the lens lit by my table lamp, I can see four reflections of the lamp. As I turn the lens from closest to infinity and then back, I (think) that I can see the deeper two images move in an unexpected way. I expected that the lights would simply move in a linear manner across the whole range of the screw. I think I see that these have an erratic kick, performing a little sideways movement along its track.
Misaligned lens cell or deformed lens possibly?
ZeissFan
Veteran
That's really unusual. A reversed lens element gives a different type of photo entirely -- nothing is really in focus or out of focus and lots of double edges on objects and such.
I might suspect a loose element. Keep in mind that some of the Novars had their lens elements held in place by snap rings rather than traditional threaded collars.
It looks to me like the film has lifted away from the film plane. There is that flat leaf spring in the takeup and feed chambers. Carefully bend them upward so that they will expert more pressure on the film. Then I'd try another roll. What film were you using? I'd go with something ordinary, like Kodak TMax 100.
I might suspect a loose element. Keep in mind that some of the Novars had their lens elements held in place by snap rings rather than traditional threaded collars.
It looks to me like the film has lifted away from the film plane. There is that flat leaf spring in the takeup and feed chambers. Carefully bend them upward so that they will expert more pressure on the film. Then I'd try another roll. What film were you using? I'd go with something ordinary, like Kodak TMax 100.
Muggins
Junk magnet
Fidget,
Apologies for thread derailment - I was startled to spot your reference to your Kershaw 450, as I've never seen another one.
Does yours have that crazy hidden shutter release and if so how do you find it?
Adrian
Apologies for thread derailment - I was startled to spot your reference to your Kershaw 450, as I've never seen another one.
Does yours have that crazy hidden shutter release and if so how do you find it?
Adrian
fidget
Lemon magnet
Hey, pleased to see another owner/user!
My Kershaw 450 is my most used folder (not only cause it's one of the few to work reliably), not much sought after (and quite uncommon). The three element lens gives a performance and look to my images which I am growing more and more to like.
I believe that they were made in Leeds, which is near to my home, so gives a further connection....
I typed a detailed response to your question, and even thought about posting some of my work from this cam. I remembered that I have been asked about this cam before, after posting some pics from it, so there may be more interest in Kershaw cams than you expect.
.....So rather than clog this thread, let's start a new thread for this........."Show us your Kershaw folder"?.........
Here is a new thread for this...
http://www.rangefinderforum.com/forums/showthread.php?t=83748
Dave...
Now to go and make a few sexy images of another folder.....well maybe not that sexy!
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