Mamiya 7 / 150 not focusing properly?

[mikeseb]

Forgive me if this is an elementary question, but I'm having trouble sorting it out. though long experienced in photography, I'm new to rangefinders.

I've owned a Mamiya 7 (not 7II)--my first rangefinder--for about three months now, shooting happily with the 80mm lens. It's tack sharp under all circumstances.

I recently added the 150, used but in excellent condition, from a reputable dealer. I probably have a few days left to return it if I need to, but I'm still sorting out the problem. Not sure if it is me, the lens, or the camera.

As I said, the 80 is tack sharp, but the 150 is soft. There appear to be things in focus in the images, but not always the things I thought I was focusing on! It appears that the plane of sharp focus is maybe three to six inches--maybe more--behind what I thought I'd focused on. The lack of focus seems more pronounced the closer the intended subject, and the wider the aperture.

I've read of the Mamiya rangefinders that focusing is more difficult with the longer lenses, due to the smaller relative size of the frame visible in the viewfinder, and I have found this to be true. But is it possible that the rangefinder can be off for one lens and seemingly spot-on for another?

Part of the trouble I'm having is that many of my images are of necessity shot at f/8 or smaller since as you know the M7 doesn't go higher than 1/500 sec, and I usually shoot ISO 400 film. So the images that do look sharp, could be so due to depth of field. I finally shot a couple of rolls of 100 speed film at f/4.5, and now the "problem" is quite apparent.--but again, with closer subjects and open apertures. Some shots taken at max aperture, but of distant subjects, apperar sharp.

Any advice on what might be amiss (including the chump on the fleshy side of the viewfinder) and how to proceed nailing this down would be appreciated. Return the lens? Send it in for calibration?

Thanks all.

Mike

 

[Ridgeway]

I've never owned the 150, but doesn't it require its own separate viewfinder? I don't think you mentioned it.

 

[pevelg]

No, it does not require a separate viewfinder, though it is an option. Either way, it would have nothing to due with focusing. From the reading I've done this is actually a somewhat common problem. Most likely the 150mm will have to be adjusted to match your camera/80mm lens.

I just started using the Mamiya 7 with 80mm lens and I love it!

 

[Turtle]

No, it does not require a separate viewfinder, though it is an option. Either way, it would have nothing to due with focusing. From the reading I've done this is actually a somewhat common problem. Most likely the 150mm will have to be adjusted to match your camera/80mm lens.

I just started using the Mamiya 7 with 80mm lens and I love it!

something is off and I would suggest the body and lens go to a service agent. I have heard of 150s that cannot be made to work reliably no matter what as well as those who have had perfect results off the bat. My friend's was miles out when he got it (new) and after service they are smack on. I have just done some tests with mine (just got into the Mamiya 7 too) and will report back.

I tried the test whereby one focuses on something over 2 miles away to see if correct indicated focus corresponds with the infinity stop. I have found it bloody hard to tell the difference between the viewfinder patch image when focused on the infinity stop and just before at such distances. When I focus on something 3/4 mile or so away I find myself settled just before the infinity stop in most cases, but have tested with it at this setting and also at infinity at about 1 mile and 2 miles. i am most interested in landscapes and so this is the biggest concern - infinity / long range focus. I also did a test on the hessian weave on some chairs about 3 m away and found this quite easy to focus. whether the results are sharp I dont know.

Seems every lens camer combo is different, sadly, but a least the 150 is available and can be made to work! when correctly calibrated it is supposedly spectacular - will report on that too!

 

[mikeseb]

more test shots today....

more test shots today....

Thanks everyone for your responses.

Did a bit more testing today. ISO 100 film, all images shot at max aperture of f/4.5 with the 150. Viewing the results, I am thinking it is more likely a photographer problem than a lens or rangefinder problem.

A variety of images of subjects both near and distant turned out quite sharp. Any focusing problem is evidently negligible based on what I'm seeing.

I am amazed at just how little DOF this lens has wide open. In one shot of a parking-lot sign maybe 9 inches wide, and angled slightly off parallel with the camera's film plane, so that one edge was maybe four inches farther from the film plane than the other, and standing perhaps 2-2.5m from the sign, only the edge I focused on was sharp--the other was out of focus! This strikes me as quite a bit less DOF than I have with the 140mm for my Contax 645 at f/2.8! (Is that optically plausible?) I also realized that on some of the images i shot, I may have been at or within the 1.8m minimum focus distance this lens is capable of.

I am likely going to send the camera in for a CLA anyway, and I'll have them check the RF while they're at it. I'll also send in the 150 so they can check the two together.

Thanks again for everyone's thoughts.

Mike S.

 

[Turtle]

Looks like mine are smack on. Did a recent test with a used 150 on a new body and the two work fine together. Have to be very careful wide open and at just short of (camera) infinity as racking it out all the way to infinity for a subject about 1km away resulted in ever so slightly soft images. True focus was achieved a couple of mm of movement short of infinity and was just discernably correct when using the rangefinder images. Not easy to see tho!