Miranda 70-210 problem?

cowasaki

cowasaki

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Helen had a few issues with this lens when she had it on her OM10 so we ended up replacing her zoom lens. I have just attached the lens to my OM10 and it appears to be ok to me but Helen is insisting that the two semi circles are out of alignment and all the shots she did with that lens were out of focus (they were out of focus actually). The lens appears to be in very good condition with no obvious signs of damage.

How does the focus screen work? I thought that the semi circles were actually etched onto a single piece of glass. They don't look "out of alignment" to me although there does appear to be a tiny amount of dirt which looks a little like a shadow and could make it appear that they are. I might take a few test shots with the last few frames of the current film.

The two semi circles seem to switch to being darker/lighter than the other as you zoom and or focus especially in lower amounts of light.

It is a manual camera and all the shots with other lenses appear in focus.

When you look through this lens you can change the zoom amount and focus.

Is there any way that this lens could be broken in such a way that it appear in focus through the viewfinder but not on film whilst both her other lenses were in focus both through the viewfinder and film.
 
Just to add to Cowasaki's question, there are things I can see with the lens, which he can't. When I look through the view finder, apart from one or other of the semi-circles appearing black - so that you can't focus properly most of the time - when you can actually see through them (by shifting the camera a bit), they don't appear to line up. The top one looks shunted to the right, and the bottom one looks shunted to the left, and I can see what appears to be damage right in the middle, where they meet, like a kink or even tiny chip. So as far as I'm concerned, the two tiny slivers of semi-circular glass are surrounded by the ground(?) glass ring, and the whole thing is sandwiched between two plates of glass. I can clearly see them out of alignment, and as such, no matter what I do, my pictures with that lens are always out of focus (as Cowasaki pertained to), but my pictures with my other lenses with identical focus screens are in focus.
 
I've just taken the lens off to show Helen the focus screen in situ from the other side and she still says they appear misaligned although, like I said, I thought that they were etched into a single thin plastic sheet so can't be misaligned. (or could it just be that this lens is totally carp)
 
Cant really help you with the mis alignment ( apart from the fact that on my Hassy focus screen they are 'etched' on the same glass, so if its a problem, it should be with the focus screen, not the lens), the 'one half blacking out' is a problem I have seen with many zoom lens, especially the ones which have smaller f stops and in low light. For example, I encounter this with my Tamron zoom ( f 4.5 at the long end) on contax RTS camera, but the same camera with prime lens ( f 2 or less) never have this problem. I read somewhere long back ( the memory is hazy on this) that at low light at smaller f stops, zoom lens have this problem. What I do, and it works sometimes, is shorten the zoom ( therefore getting the widest aperture to 3.5), the problem goes away, focus, then adjust the zoom, and shoot. Another bizzare thing is , you shoot in lower light, one half goes black, and stays black, till I point the lens to brighter light, and both gets bright. Then I point to the darker space; and somehow it stays bright. No idea why this happens; except to say, the lens genie is at work again....

No wonder my daughter says it takes me for ever to get one shot.....
 
ujjwaldey8165 said:
Cant really help you with the mis alignment ( apart from the fact that on my Hassy focus screen they are 'etched' on the same glass, so if its a problem, it should be with the focus screen, not the lens), the 'one half blacking out' is a problem I have seen with many zoom lens, especially the ones which have smaller f stops and in low light. For example, I encounter this with my Tamron zoom ( f 4.5 at the long end) on contax RTS camera, but the same camera with prime lens ( f 2 or less) never have this problem. I read somewhere long back ( the memory is hazy on this) that at low light at smaller f stops, zoom lens have this problem. What I do, and it works sometimes, is shorten the zoom ( therefore getting the widest aperture to 3.5), the problem goes away, focus, then adjust the zoom, and shoot. Another bizzare thing is , you shoot in lower light, one half goes black, and stays black, till I point the lens to brighter light, and both gets bright. Then I point to the darker space; and somehow it stays bright. No idea why this happens; except to say, the lens genie is at work again....

No wonder my daughter says it takes me for ever to get one shot.....
Click to expand...

We were both sat in the same room with it and she kept looking out of the window and saying see it is doing it and I looked out of the window into a brighter area and couldn't see it. I did have my suspicions, which I voiced to Helen, that it might be down to lack of light with this zoom which is a f4.5 and larger!
 
re focusing, what I do is take a fixed spot on the wall, focus it with 2 cameras ( one is the RTS, very accurate) and see what the 2 lens say the distance is. I repeat for various distance, usualy 2, 5 and 10 and 15 feet. Beyond that it will not usually matter to me, especially if its a wide lens. You could do it to see if the OM10 lens are showing the correct distance
 
semi circles are on the camera, not the lens. The larger your f number, the less light you get and the semi circles become harder to see, one or both going dark - that's why there is a matt screen and other aids on the finder as well... to make the best of what light you have.
 
Do you see the problem with just this lens? It could be that the focus screen isn't seated properly. Check with a 50/1.8 or something.

The problem of the image going black is common and just something you have to work around.

ujjwaldey8165 said:
What I do, and it works sometimes, is shorten the zoom ( therefore getting the widest aperture to 3.5), the problem goes away, focus, then adjust the zoom, and shoot.
Click to expand...

Do be aware that some lenses change their focus point as you zoom.
 
Most of the 'problems' were as I assumed. The only unexplained problem now are all the images taken with it being slightly blurred. This may just be the lens although it could be that Helen couldn't focus with it.
 
I figured out for myself that it was a lack of light making the semi-circles go black, and because it's just doing it with just the zoom lens and not the others. But they do still look out of alignment, but I'm assuming that the smaller lenses just don't magnify such anomalies like the zoom lens does. And less of the "told you so" attitude thank you Mr Cowasaki! :nono:
 
Oh, and thank you to all the peeps who've answered my query. I still think it's a poo lens as all my pictures are out of focus, and contrary to what Mr C says, I am more than capable of focusing with such a camera - had an OM10 for donkeys back in the 80's/90's and every picture was as crisp as a crisp thing.
 
Well, if they are out of alignment now then they have *always* been out of aligmnent. It's not something that can suddenly happen, it would be like... well, draw two parallell lines on a piece of paper... wait for one of them to move relative to the other - not going to happen is it? The semi-circles are part of a glass screen, a *one-piece* glass screen, made, ground, polished, finished as one piece. No moving parts to go out of alignment.*


Arthur

* Unless the screen itself has moved but then it would be so for all lenses.
 
Ambermile said:
Well, if they are out of alignment now then they have *always* been out of aligmnent. It's not something that can suddenly happen, it would be like... well, draw two parallell lines on a piece of paper... wait for one of them to move relative to the other - not going to happen is it? The semi-circles are part of a glass screen, a *one-piece* glass screen, made, ground, polished, finished as one piece. No moving parts to go out of alignment.*


Arthur

* Unless the screen itself has moved but then it would be so for all lenses.
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As I said, the smaller ones don't magnify what I'm seeing like the zoom lens does, either through the viewfinder or on film. I was merely telling peeps what it looks like to me - it must be an optical illusion then, but the fact that it always produces blurred pictures when my other lenses produce crisp pictures, either means it's a cheap, rubbish lens or I'm rubbish at using zoom lenses. Actually that's probably the case (the latter), because when I had a Canon (sorry for swearing!) EOS 300V, I couldn't get decent pictures with that zoom either! I guess it must be me!!!
 
This may be a "Sucking Eggs" comment - but are you sure it's out of focus blur, not camera shake blur? The old maxim of minimum shutter speed = 1/focal length is especially true with older non Image-Stabilised lenses.

I mention this, as I ran a film through my recently aquired Canon A-1, with a 75-200 lens on the front, and the first few shots were a bit ropey, until I remembered. I'm normally okay at 1/100th at 200mm with the EOS-3 and a non IS lens (old EF 80-200 f2.8L), but that combo balances quite well - the A-1 is fairly tiny and light in comparison, and the FD 75-200 dwarves it, so it's not as well balanced.
 
TheBigYin said:
This may be a "Sucking Eggs" comment - but are you sure it's out of focus blur, not camera shake blur? The old maxim of minimum shutter speed = 1/focal length is especially true with older non Image-Stabilised lenses.
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That's a very good point. I hadn't thought of that. I don't mind you teaching this grandmother to suck eggs - never too old to learn! It may well be my problem, thanks.
 
there's an easy way to check - stick it on a tripod for one, then same shot, same settings hand-held :thumbs:
 
Yes, hubby's got a film in his OM10, so he said he'll try doing just that. Thanks for the advice.
 
Yep, will give it a try on my OM10 over next few days. There is a Kodak BW400 in it at the moment. I was going to use the OM10 for IR :thumbs: So will need a bit of advice on that film wise but will post a thread
 
cowasaki said:
Yep, will give it a try on my OM10 over next few days. There is a Kodak BW400 in it at the moment. I was going to use the OM10 for IR :thumbs: So will need a bit of advice on that film wise but will post a thread
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I'll be checking that thread myself - one of the reasons I got hold of the A-1 was that it didn't have the IR film sensor like the EOS-3 had, so I could try some IR film. Of course, the other reasons were a) it was cheap - as in swap for a few framed prints from a local sporting event and b) I had a AE-1 BITD, but always wanted the A-1, still had a few lenses left after the camera was nicked from my van, just couldn't afford it :lol:
 
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