Infinity focusing

[seany65]

Hello all, yet another thread that I'm not sure about where to put it, but:

Is it possible for a camera to be able to focus properly at all distances with a standard lens and a telephoto lens but not with a wide angle lens?

I suppose we could open this up to cameras being able to focus properly with wide-angles and standards but not with telephotos or any combination.

I ask because I tried a 45mm lens on my Mamiya M645 1000S and the combo couldn't even focus on the houses opposite me in the square where I live, but both my 80mm and 150mm work properly. I know that you're probably thinking "obviously it must be the 45mm lens's fault" but I'm still worried that it could be the camera. I'm looking for another 45mm lens (almost all seem to be in Japan, and those that are in the UK have sellers who won't accept returns), and I'd like my two braincells to be put at ease.

I suppose we could open this up to cameras being able to focus properly with wide-angles and standards but not with telephotos or any combination.

Any help would be much appreciated.

 

[Retro-Grouch]

Does the camera have a focusing screen with focusing aids, such as a split image or microprism? These shouldn't make a difference, but I've occasionally run into some minor crankiness with these. Also, it sounds like your lens won't focus to infinity. Is that the case?
I'd take a very close look at the lens element retaining rings, etc., to see if the lens has been opened up for repairs. As I'm sure you know, there are some very ham-fisted "repair" people out there, and your lens might be a victim of one.

 

[joe bosak]

I've done that. Easy to take some lenses apart (like the 45mm Mir), not too bad getting them back together so they at least look like a lens again. But tricky to get the focusing helioid lined up correctly lined up if it's your first time. May not be your problem, but it happens.

 

[Sonnar Brian]

I would suspect the lens.
Do you know the history of the camera and lenses that focus properly on it? If they have always been together, it is slightly possible that the camera and those lenses were "zeroed", ie calibrated together. Much more common on Rangefinder cameras and lenses. But- possible.

Again: 99.99% it os the wide-angle lens. Check if there are shims under the mount or in the barrel of the elns fitting into the focus mount. It is out too far, needs to be reduced.

 

[seany65]

Thanks for the replies. I have no idea of the history of the camera or any of the lenses. I don't even know if the 80mm was bought at the same time as the camera or sometime after, or even before if it was for an original M645. The 45mm and 150mm were each bought from different sellers and I only had the money for the 150mm after the shop refunded the 45mm.

The camera does have the microprism/45 degree split image screen which is more than clean and bright enough even for indoor work. The 80mm and 150mm focus at all distances fully. I checked both carefully after the trouble with the 45mm.

The slightly puzling thing is, that the shop told me it would take 6-8 weeks to come back from the tech, so they basically shoved a refund at me without asking if I wanted one and they said they'd let me know when they got it back, and yet it seems to have been a much shorter time than that when it was relisted by them. Mind you I'm not surprised they didn't tell me as I wouldn't change my Neutral feedback to Positive as they'd described it as "Mechanically:10", which it couldn't be as it couldn't focus to infinity or even to the houses opposite mine and they're just a 100 feet away (or a bit less - I don't have a laser rangefinder to check properly).

Thanks for setting my mind at rest about the problem probably being with the lens. I only wish I'd thought of getting the serial number of it so that I don't end up with it again.