External Viewfinder Woes

[zauhar]

I had the 28mm metal CV finder and found the distortion so horrid that it was impossible to actually judge of the image was level. That may be the problem rather than the frame mask being off.

Chris, I agree, the distortion is pretty bad. However, it bothers me that the rotation is always about the same angle, and in the same direction.

So from your point of view is the only option to shell out for a Genuine Leitz VF? ;-(

Regarding the comments from other folks about this rotation being a byproduct of the angle I was at - I have now had numerous experiences where I make damn sure I am facing the wall/object head on, and carefully align horizontal edges with the framelines - in my second example above I moved myself into position so that I was squarely facing the storefront, carefully aligned with the VF frame lines, and yet still there is this significant rotation.

Thanks!

Randy

 

[rogerzilla]

Off-topic, but cheap digicams with optical VFs used to do this, simply because the tiny CCD hadn't been fixed straight. Few of them have VFs nowadays so it doesn't matter.

 

[250swb]

the distortion is pretty bad. However, it bothers me that the rotation is always about the same angle, and in the same direction.

Well, obviously not wanting to tread on toes since you consider an equipment failure is the answer, but have you tried leaning the other way?

Steve

 

[dave lackey]

Well, obviously not wanting to tread on toes since you consider an equipment failure is the answer, but have you tried leaning the other way?

Steve

Well, I hope this gets resolved and am interested in the final solution. :angel: On a lighter note, sometimes focusing fluid (beer) will introduce the opposite distortion so that it cancels out....😛... if not, then you need more focusing fluid.

 

[peterm1]

I dont know about this particular VF but I have some that have a crooked internal frame mask (an old Canon one comes to mind.) Furthermore I find that this is a problem even without an external finder.

It might also be that you are "off square" when taking the image. The shots you have posted look as if you are not diretly in front of the subjects. If you are not directly in front of your subject then of course not all edges in the image will be aligned. It may be that the VF and the lens in use register the scene differently so what looks aligned in the VF is rendered as more askew by the lens - because wide angle lenses tend to exaggerate perspective of course and this may be less obvious in your finder.

Whether shooting DSLR, Leica M or small sensor digital, I will often find that what looked well aligned in the finder / on the screen is not so in the final image. I try my best but recognise that getting good alignment is inherently difficult. I always post process my images and recognising this, the very first edit I make with almost every image is almost always to adjust the image framing to make sure that alignment is correct.

I happen to use Corel Paintshop Pro X4 and this has an excellent tool for this purpose - just drag an onscreen line so that it aligns with a picture element that you want to be either vertical or horizontal and then click. The software rotates the image accordingly and automatically crops to the new border line. It also has an equally effective perspective correction tool to correct out of square buildings etc.

 

[zauhar]

Hey Dave, Steve :

Any chance either of you are in the market for a 21mm VF? Clearly there is nothing wrong with it, and I will happily sell it to you at an excellent price. It was $185 new just a few months ago, you can have it for $100 in the original box! That will help me defray the cost of a used Leica VF.

Steve: Actually, if you don't want to buy the finder, I plan on trying exactly what you suggest - I am going to frame, switch to the main VF to correct any tilt, and then shift back to shoot.

Dave: Hope all went well with the doc today.

Randy

 

[zauhar]

I dont know about this particular VF but I have some that have a crooked internal frame mask (an old Canon one comes to mind.) Furthermore I find that this is a problem even without an external finder.

It might also be that you are "off square" when taking the image. The shots you have posted look as if you are not diretly in front of the subjects. If you are not directly in front of your subject then of course not all edges in the image will be aligned. It may be that the VF and the lens in use register the scene differently so what looks aligned in the VF is rendered as more askew by the lens - because wide angle lenses tend to exaggerate perspective of course and this may be less obvious in your finder.

Whether shooting DSLR, Leica M or small sensor digital, I will often find that what looked well aligned in the finder / on the screen is not so in the final image. I try my best but recognise that getting good alignment is inherently difficult. I always post process my images and recognising this, the very first edit I make with almost every image is almost always to adjust the image framing to make sure that alignment is correct.

I happen to use Corel Paintshop Pro X4 and this has an excellent tool for this purpose - just drag an onscreen line so that it aligns with a picture element that you want to be either vertical or horizontal and then click. The software rotates the image accordingly and automatically crops to the new border line. It also has an equally effective perspective correction tool to correct out of square buildings etc.

Peter, thanks for that suggestion.

I may have been slightly off-center in the first example above, but in the second I was really square in front of the building, and really, really carefully aligned that sign vs. the framelines. I have repeated that experiment, and keep getting the same result.

I am too old, and have f--cked up too many things, to think that I can't possibly be at fault; but I am at least a little suspicious of this VF. ;-)

Randy

 

[Leigh Youdale]

Can't spend the time dredging through all the responses to see if this has been covered but my immediate thought was that using the edge of the viewfinder is almost guaranteed to result in the problem you complain of. The optics of the VF aren't going to be that much different to the optics of the lens when it comes to distortion. The only place the VF is going to render a "straight" image is right in the centre. Hairlines on the VF might help but using the edges to try to get levels right is not going to work, in my opinion.

 

[ferider]

I've had a CV 28 metal finder with twisted framelines. Checked and fixed it by using a flash-shoe bubble level and a tripod. I've also had a CV mini finder with parallax correction line at the bottom of the finder. Not too difficult to fix either.

It happens ....

Then again, for 28 and wider, if you want really straight horizons, an SLR might be the better tool.

 

[zauhar]

I've had a CV 28 metal finder with twisted framelines. Checked and fixed it by using a flash-shoe bubble level and a tripod. I've also had a CV mini finder with parallax correction line at the bottom of the finder. Not too difficult to fix either.

It happens ....

Then again, for 28 and wider, if you want really straight horizons, an SLR might be the better tool.

So did you unscrew the back retaining ring? Then just twist the glass a little?

Thanks!

Randy

 

[ferider]

On the 28 finder, there is a thin cover washer that you have to remove first. Then you can unscrew the retaining ring, have to unglue the rear element, twist it and glue it back in place if I remember right.

Cheers,

Roland.

 

[zauhar]

Here is the best view I can get of the view finder:

The bottom line I added is along the bevel on the rear, which should be exactly level; the other lines are tangent to the framelines, as best I can make them. I tried to take this phone picture as head-on as possible, but there is only so much I can do,.

Anyway, to me the frame lines look rotated w.r.t the horizontal. Or just my imagination?

Randy

 

[Ken Ford]

Anyway, to me the frame lines look rotated w.r.t the horizontal. Or just my imagination?

Randy

Concur. And pretty severely rotated at that!

 

[zauhar]

Concur. And pretty severely rotated at that!

Thanks Ken.

Maybe I should re-post this photo and resurrect the "Cosina-Voigtlander Quality Control" thread. ;-(

Seriously, I don't know what to do about this. Sort of late for a return to CameraQuest, and I would not sell this to someone else. I might ask Steve Gandy what he thinks.

Randy

 

[santela]

damn, i was considering buying a 21mm voigtlander finder... now i have to reconsider.

 

[batterytypehah!]

My, that's really very obvious! Sorry for my alternative explanation before.

With the proviso that I'm not familiar with this particular finder at all:

If you're lucky, the optics module in there is simply one cemented, cylindrical block. I've had one or two apart that were like that, however they were normal/moderately wide FOV. This design works well enough but it depends on accurate assembly (and proper QC!) because the block is free to rotate inside the housing, and only held by friction once the retaining ring is tightened.

Which would also explain why it's off in the clockwise direction; very likely, it was level before the retaining ring went on, and then moved along with the ring a little when that was tightened. The art is to have it skewed just right in the CCW direction so that it ends up level.

If it were mine, I'd try to loosen the ring a little and see if that frees up the block inside to rotate it back. I'd just pinch both glass surfaces between my thumb and index finger (with clean nitrile gloves for good friction) and twist.

 

[zauhar]

My, that's really very obvious! Sorry for my alternative explanation before.

With the proviso that I'm not familiar with this particular finder at all:

If you're lucky, the optics module in there is simply one cemented, cylindrical block. I've had one or two apart that were like that, however they were normal/moderately wide FOV. This design works well enough but it depends on accurate assembly (and proper QC!) because the block is free to rotate inside the housing, and only held by friction once the retaining ring is tightened.

Which would also explain why it's off in the clockwise direction; very likely, it was level before the retaining ring went on, and then moved along with the ring a little when that was tightened. The art is to have it skewed just right in the CCW direction so that it ends up level.

If it were mine, I'd try to loosen the ring a little and see if that frees up the block inside to rotate it back. I'd just pinch both glass surfaces between my thumb and index finger (with clean nitrile gloves for good friction) and twist.

Thanks for that detailed response - if worse comes to worst, I will try what you suggest.

First however, since I bought this new, I am asking the seller if it might be possible to do something to make things right.

Randy

 

[Ken Ford]

damn, i was considering buying a 21mm voigtlander finder... now i have to reconsider.

I wouldn't let one bad example scare you off!

 

[spencewine]

I had the same problem with the 21mm VC finder....

I had the same problem with the 21mm VC finder....

I bought the VC 21mm finder for my 21mm Zeiss ZM and had the same problem that you are having (same angle of tilt and about the same amount of tilt). It was very frustrating when I got back 25 rolls of film from Yosemite all with a nice tilt included. After that, tried to compensate by tilting my camera to get a straight horizon. At last, I ended up buying a Zeiss 21mm VF and my photos no longer suffer from the tilt. The problem is that the Zeiss 21mm VF will cover a small portion of the shutter speed dial when mounted on an M. I use mine on a Bessa-T and it works fabulously, but on the M I can't see what shutter speed I'm at because of the overlap. Something you might want to consider.