mellais

Ok everybody,

Problem solved. I didn't take into consideration that when calculating the aperture f-value, we have to use  the diameter of the lenses so called  entrance pupil — not the actual size of the iris, but rather its magnified image as seen through the front of the lens as Jay Holben points out in an article published on the American Association of Cinematographers' website (visited on April 8, 2024, see https://theasc.com/blog/shot-craft/the-entrance-pupil-of-the-lens).

So the camera should work as intended - time to put it back together and start shooting. 

P.S. 

This made me think of a possible modification; since there is room for wider movement in the diaphragm itself than what is being used, I will see if I could rebuild the linkage between the aperture ring and the lever making it possible to use the aperture to its full potential. At the very least one could get f22 instead of f16 min aperture and possibly a max aperture beyond f1.8, if the lens design allows it.

4 hours ago, arthur_mcculloch2 said:

mellais, am I right that it's a seikosha shutter? You may be able to get some further advice on the Learn Camera Repair' facebook site. I am about to open up my first seikosha-rapid in the next couple of weeks - it's in an airesflex TLR that has been sitting around for some decades, and is gummed up. Regards, Arthur.

Arthur,

I'll see if I can get further assistance in that fb group. The shutter here is Seiko-SLV and it's pretty robust, well-built. I hope you will have a good time with the Airesflex, those are interesting cameras! 

10 hours ago, arthur_mcculloch2 said:

Hi kmac. 'You can't really make a mistake reassembling them': I have (at least on a synchro compur), by putting the blades in back the front. They still fit the pins, look proper, but when actuated, close, then reopen in the rest state. From the photo, it does look more like f22 than f16 to me. But that is guessing. For the widest aperture, I've heard that, for instance, that the f2.8 xenon used in the retina IIa was simply the f2 lens with the aperture not opening as wide - but that could be an urban myth. Regards, Arthur.

Arthur, and all others, 

Thank you for your comments. I got this camera in very clean condition but certain things indicated that someone had at least taken out the front lens group earlier. In addition to that the rear lenses were oily. I'm starting to believe there is something misaligned around the diaphragm.  Whether it's aperture blades placed upside down or what I can't tell yet. But here's an update explaining why I still think there's something wrong. 

The 1st photo here shows the linkage between the aperture ring and a lever moving the blades; it's pictured here with the aperture ring turned all the way to its widest f1.8 end, and you can see how the sort of "fork" holding the lever actually makes the lever stop before the blades are fully open, as seen in the 2nd photo here. Without the fork in place, the lever can move all the way to the stop (Photo 3). 

Everything seems to be in their proper places and you get the feeling that this aperture ring linkage is working as it should, the fork and lever and everything fitting together perfectly. Yet the max aperture you get with this lens as it is now is still only roughly 14-15mm in diameter. My math says it's not equal to f1.8. 

I will have to take out the whole shutter mechanism to access the diaphragm. 

1 hour ago, John Seaman said:

I don't see how the assembly of the blades themselves could cause this, more likely there is some issue with the linkage between the blades and aperture ring. I would be inclined to leave it and compensate for the error by selecting an aperture one stop wider than that required.

Thanks John, 

I'll have a look at the aperture ring and its linkage, possible stoppers etc. At the moment the ring turns seemingly correctly from f1.8 position to f16 position and stops at both ends. So there's no room for correction at these extreme values. The aperture openings still look odd to me, usually even f22 is not that tiny and I feel it should open up wider at the lenses max aperture.

Hi, 

Please have a look at the attached two photos for reference. I have a newly acquired Minolta Minoltina-s rangefinder camera and I am cleaning its lens elements. While at it, I keep looking at the diaphragm and the aperture opening vs aperture ring setting; I am not sure if the blades are correctly installed (by some previous owner). The smallest f16 setting looks really small in my experience and the widest f1.8 does not seem to open up as wide as it should be. 

So my question is: if the measurement for the smallest aperture available is approximately 1,4mm in diameter, and the widest is 14,6mm, can I just check the corresponding f values by dividing the focal length 40mm by these values? It gives me roughly f28 and f2.8, telling me that the blades are not correctly installed.

I am trying to avoid rebuilding the diaphragm if possible because it is clean and smoothly functioning and difficult to access but of course it would have to be correctly built as well. 

Many thanks for your comments,

Regards 

Otto

Hi,

A potential fixer issue;

HP5+ shot @1600 and developed in Rodinal (semi-stand). I'm new to this combo. Films get developed without problems but my negatives come out slightly fogged even after very thorough fixing.

The fixer comes from an older opened container but tested ok before use.

In the photos you can see that the base is almost clear but still shows fog.

I have ruled out film storage issues.

Is the fixer done or is this what it's supposed to look like with this film/developer? It's the same film clip in both images attached;)

Regards

Otto

That film looks like it hasn't been developed at all. There's no outer edge frame numbers and no frame separators. Can you post more information about the processing ?

That was my initial reaction too. I asked the lab about it but they haven't given me any answer yet. Is it really possible to develop a film so that you cannot see the frame numbers and frame separators?

Feels weird.

Otto

Hi,

I recently shot a roll of ancient Ektachrome 64 slide film. Expired in 1979, no idea how it had been stored.

I have a few rolls of this stock so I'm testing. I decided to start with this roll at near box speed (50ASA) exposure and regular development.

Terrible results - or, more like no results at all. See the image.

Any ideas where to go with the next roll? Heavy overexposure, longer development time, both, or what?

Many thanks for your comments.

Regards

Otto

Had a couple of MTL3s in my youth (must be good - fits Pentax lenses), and discovered an anomaly. When attempting to wind on at the end of the roll, if there was insufficient film in the cassette to complete the lever stroke, it was IMPERATIVE to depress the rewind button and complete the stroke before rewinding the film, or else the shutter jammed. Don't know if that was the case with all the MTL series, but it certainly happened on the two I had, before I replaced the second with a Cosina CT1G.

Thanks, I'll pay attention to that.

BTW, I have had terrific luck with the various Helios lenses. I suspect their quality control was a lot better than the 'neigh'-sayers would have it.

I agree. Mine does have a tiny bubble inside one of the lens elements - well I've decided it's not a problem. Otherwise excellent build quality. But let's wait for the pics before giving my copy a final verdict.

Thank you John,

That's what I thought - pressing both simultaneously would feel irrational. But you never know - even contemporary product design can surprise you sometimes:)

Will post the results in my gallery and let you know.

Hi,

I am shooting my first roll with Praktica mtl3 and Zenit Helios 44M-4 58mm f2 lens. What a feeling!

I have one question:

I understand that I need to push the metering button in order to let the camera stop down and meter exposures. But when I'm finally taking a photo, do I have to hold it down when pressing the shutter button - or does the camera stop down to the right aperture also when simply pressing the shutter button alone?

Thanks for your help.

Otto