zauhar
Veteran
Hi all,
I have had some ongoing irritation with framing when using my 21mm SA with a Cosina external VF, on my M3. I am continually getting unwanted rotation of the image, like these:
In each case I carefully line up edges in the scene (the roof of the building in the first example, the sign in the second) with the bright lines in the external VF. This rotation is consistent across a number of images, so I started experimenting a little with the VF this morning. Looking up at the line where the ceiling meets the wall, I lined up this edge with the top frame lines of the external VF, then shifting carefully to look through the M3's main VF - I see that the camera is rotated slightly counterclockwise from horizontal (along my line of sight), so the resulting image would be rotated clockwise (as seen in the images).
Is this a common problem? Am I doing something wrong? Is this the best I can expect from this "less expensive" VF?
Thanks!
Randy
I have had some ongoing irritation with framing when using my 21mm SA with a Cosina external VF, on my M3. I am continually getting unwanted rotation of the image, like these:
In each case I carefully line up edges in the scene (the roof of the building in the first example, the sign in the second) with the bright lines in the external VF. This rotation is consistent across a number of images, so I started experimenting a little with the VF this morning. Looking up at the line where the ceiling meets the wall, I lined up this edge with the top frame lines of the external VF, then shifting carefully to look through the M3's main VF - I see that the camera is rotated slightly counterclockwise from horizontal (along my line of sight), so the resulting image would be rotated clockwise (as seen in the images).
Is this a common problem? Am I doing something wrong? Is this the best I can expect from this "less expensive" VF?
Thanks!
Randy
dave lackey
Veteran
Hi all,
I have had some ongoing irritation with framing when using my 21mm SA with a Cosina external VF, on my M3. I am continually getting unwanted rotation of the image, like these:
In each case I carefully line up edges in the scene (the roof of the building in the first example, the sign in the second) with the bright lines in the external VF. This rotation is consistent across a number of images, so I started experimenting a little with the VF this morning. Looking up at the line where the ceiling meets the wall, I lined up this edge with the top frame lines of the external VF, then shifting carefully to look through the M3's main VF - I see that the camera is rotated slightly counterclockwise from horizontal (along my line of sight), so the resulting image would be rotated clockwise (as seen in the images).
Is this a common problem? Am I doing something wrong? Is this the best I can expect from this "less expensive" VF?
Thanks!
Randy
Working on my third cup of coffee and headed off to the hospital for more lab work but try as I might, I can't grasp what you're saying. Are you saying the level point (horizon or whatever) seems tilted? Please help me understand this as the external VF can not affect the image any other way than tilting and cropping as far as I know. But, then, this morning I really don't know much.
But what I think I see is just the normal distortion of a wide angle lens. Looking at the bottom of the images, horizontal lines are parallel with the bottom of the image and it gets "tilted" as you go up the image....
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gns
Well-known
I have the metal 28mm and 35mm finders and they are pretty straight.
Try doing a better test with the camera on a tripod or something solid.
Gary
Try doing a better test with the camera on a tripod or something solid.
Gary
Ken Ford
Refuses to suffer fools
I'm seeing it - like the brightline mask is off horizontal.
Can you possibly add a shim made from electrical tape to the right side bottom of the VF shoe to jack up that side and see if it corrects the tilt? If it does, you can pursue a more permanent fix.
Can you possibly add a shim made from electrical tape to the right side bottom of the VF shoe to jack up that side and see if it corrects the tilt? If it does, you can pursue a more permanent fix.
zauhar
Veteran
Working on my third cup of coffee and headed off to the hospital for more lab work but try as I might, I can't grasp what you're saying. Are you saying the level point (horizon or whatever) seems tilted? Please help me understand this as the external VF can not affect the image any other way than tilting and cropping as far as I know. But, then, this morning I really don't know much.
Sorry Dave, I tried to be as clear as I could - I am saying that the bright lines on the VF may be leading me astray - i.e. maybe they are not truly level. Obviously if the framelines are twisted, my images will be too.
But, I am not sure if there is some other problem - that is why I was seeking some collective wisdom.
Hope all goes well at hospital, sorry you need to go there.
Randy
zauhar
Veteran
Ken, I can certainly try that.
Gary, I don't have a tripod but I can look for some place I can rest the camera while framing.
I was doing some additional searching, and found a discussion on the Leica forum comparing Zeiss finders with Leica - the claim was made that the Leica finder compensates for the fact that the shoe is not centered over the lens on Leica bodies, while for Zeiss this is not the case. The poster claimed this led to framing errors and "rotation". Could that be an issue with the Cosina VF?
Randy
MaxElmar
Well-known
Just put the rig on a tripod or level surface and test it. Keep notes. Use the results to manually adjust or have the VF adjusted. The metal CV finders look like they can be disassembled by removing a retaining ring in the front. It's certainly possible that that particular CV finder is off, and it's likely that it can be put right by a knowledgeable tech. If it's a plastic CV finder just sell it to someone willing to deal with it and get another finder.
MRohlfing
Well-known
You could try the Voigtlander Spirit Level
http://www.cameraquest.com/voigtacc.htm
I like that thing a lot, as I often unintentionally tilt my camera. It needs a Double Accessory Shoe, so both the finder and the spirit level can be mounted to the camera.
Both seem to be sold out, but you might be able to find a used one.
http://www.cameraquest.com/voigtacc.htm
I like that thing a lot, as I often unintentionally tilt my camera. It needs a Double Accessory Shoe, so both the finder and the spirit level can be mounted to the camera.
Both seem to be sold out, but you might be able to find a used one.
rbiemer
Unabashed Amateur
Randy,
Have you got a level? Carpenters' level or bubble level?
Tripod or not, you want to make sure the camera is dead level and then see how your scene looks through both the camera VF and the external VF.
I like Ken's suggestion as well.
On a possibly related note, do you wear eyeglasses? I wear glasses to correct for astigmatism( and far sightedness but that's not important for my point here) and the
previous pair I had were very slightly rotated from level and this gave me about two years of slightly skewed horizons!
I don't think the VF being horizontally displaced from the center of the lens would lead to the frame being skewed; if you have the camera leveled, the framing mught be off a bit but the VF, if the bright lines are correct, would still be level just displaced side to side a bit.
Rob
Have you got a level? Carpenters' level or bubble level?
Tripod or not, you want to make sure the camera is dead level and then see how your scene looks through both the camera VF and the external VF.
I like Ken's suggestion as well.
On a possibly related note, do you wear eyeglasses? I wear glasses to correct for astigmatism( and far sightedness but that's not important for my point here) and the
previous pair I had were very slightly rotated from level and this gave me about two years of slightly skewed horizons!
I don't think the VF being horizontally displaced from the center of the lens would lead to the frame being skewed; if you have the camera leveled, the framing mught be off a bit but the VF, if the bright lines are correct, would still be level just displaced side to side a bit.
Rob
gns
Well-known
It's a simple test, but you can't do it hand-held. Set the camera on a solid table facing squarely at wall. If there is no convenient horizontal line to use, then put a strip of masking tape or similar on the wall lined up parallel to and just under the upper frame line. Then look at the neg to check for square. As I said, my finders are pretty square. Maybe not perfect, but much better than I need to worry about considering how straight/steady I can hand hold a camera.
Gary
zauhar
Veteran
This is a metal finder - the framelines are etched on the rear element, which does seem to be held in placing by a retaining ring. Maybe I can just reposition it?
Randy
zauhar
Veteran
Rob, I do wear glasses which is why I got an external VF with frame lines, so if my glasses produced some distortion I would have the lines to compare against. I honestly think they might be a little off, in which case they do more harm than good.
Randy
250swb
Well-known
Looks like the normal distortion of a wide lens to me, and when you are photographing a scene with extreme perspective the mismatch between what you see through the viewfinder and what the lens sees will show up. I regularly swap between a plastic 21mm CV finder and a plastic Leica finder and don't notice any difference in framing accuracy, except to say both are approximate and this is exaggerated the closer to the subject you are.
Steve
Steve
Mark Wood
Well-known
I had exactly the same problem with a 35 mm CV plastic viewfinder. With these, the rear glass (which is actually circular and has the framelines etched onto it) just slots in and can rotate in its slot to put the frame at whatever angle you like. The two halves of the plastic viewfinder can be separated by removing a few screws and the rear element is then easily repositioned to align it properly with the camera finder. Whether mine was like this when it left the factory or it moved at some point I've no idea as I never noticed it until I took some photographs.
I'm not sure how the metal finders are made or how they come apart though I'm afraid.
I'm not sure how the metal finders are made or how they come apart though I'm afraid.
zauhar
Veteran
Steve, I realize that the lens distorts lines a lot, but if I am facing a horizontal line head-on, should it not render horizontal on film?
Stated a another way, a wide-angle lens can surely capture an image of a level horizon, provided the camera is level?
That's the problem - I think that by lining horizontal edges up with the framelines, I am tiling the camera, although as others pointed out I need to experiment some more to confirm that.
Thanks!
Randy
zauhar
Veteran
The metal VF I have has a retaining ring, which looks like it can be removed (although I may mess it up if I use pliers). Maybe I could then reset the orientation of the glass, although I suspect that would be a tricky operation. It surely require multiple experiments to get it right.
Randy
Chriscrawfordphoto
Real Men Shoot Film.
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.
batterytypehah!
Lord of the Dings
I agree with Dave (best wishes!) above, I'm not sure that there is a problem in the first place. Both of these shots appear straight to me at ground level.
Yes, if you take a picture of a level horizon (the sea, ideally), it should just remain level. Your shots are of buildings, though. You have to be level and square for the upper edge to remain parallel. That is, the camera parallel to the ground and parallel to the wall you're facing.
Yes, if you take a picture of a level horizon (the sea, ideally), it should just remain level. Your shots are of buildings, though. You have to be level and square for the upper edge to remain parallel. That is, the camera parallel to the ground and parallel to the wall you're facing.
Mark Wood
Well-known
True, with the metal finder it would probably take a few attempts to get it straight. The old plastic finders are relatively easy of course as you have the straight edge of the plastic casing to help.
Steve M.
Veteran
Set the camera on a flat surface like a table top and focus on something (like a kitchen counter) that you know is relatively level. Make sure you're directly in front of whatever you're using, not angled a little to either side. If the view in the internal VF is level, and the one in the external one isn't, there's your problem. Or, if you haven't had this problem w/ other lenses using your M3's internal frame lines, there's the problem too.
I sometimes get horizon lines that are out of whack because I'm not holding the camera exactly straight. Hard to explain, but if you're not dead center to your target, and off just a little on the horizon alignment as well, things can look pretty bad even w/ a 50mm lens. SLR's usually don't give me this issue as I'm seeing what the lens is seeing (except it's upside down, and the mirror is flipping the image).
I sometimes get horizon lines that are out of whack because I'm not holding the camera exactly straight. Hard to explain, but if you're not dead center to your target, and off just a little on the horizon alignment as well, things can look pretty bad even w/ a 50mm lens. SLR's usually don't give me this issue as I'm seeing what the lens is seeing (except it's upside down, and the mirror is flipping the image).