Issues with Mamiya N 65mm

[RFH]

I just managed to make a trade for the camera I've wanted for quite some time, the Mamiya 7.

Unfortunately, I have some focus issues with the 65mm, and I want to hear if anyone has a suggestion as to what might be the problem - and better yet: a solution.

The previous owner claims that it's all in order. He seems like a serious photographer, so I find it odd that he would not have recognised such an obvious defect.

It appears that the lens is sharp only in the very center, and then it gradually tapers off toward the edges and corners of the frame, where it is totally mushed out. Using a smaller aperture doesn't improve the situation much.

The resulting images look like they were shot with a Holga or some cheapo plastic lens. And that's not what I expected from seeing the amazing 65mm shots in the Mamiya 7 thread here on RFF.

The 80mm works fine and is sharp across the frame. So I don't suppose the fault lies with the camera body or the film flatness or loading. My scanner is also fine; the unsharp areas are clearly visible on a light table with a loupe.

Here are a few test shots of the mandatory brick wall.


At f4:

Lower right:

At f11:

Lower right:

 

[charjohncarter]

Is there evidence of the lens having been work on? If the RF works with the 80mm and the photos are good with that lens then the film flatness should also be good. Sometimes, home done CLAs of lens get the back element in backwards.

 

[RFH]

No, I can't discern any obvious signs of DIY repair. The rear element has the convex end outwards, as it should be per the lens diagram published by Mamiya. No signs of damage or any other visible defects.
But thanks for the suggestion.

 

[charjohncarter]

No, I can't discern any obvious signs of DIY repair. The rear element has the convex end outwards, as it should be per the lens diagram published by Mamiya. No signs of damage or any other visible defects.
But thanks for the suggestion.

Well, something is wrong. My 65mm f6.3 for a Super 23 is totally sharp, and my friend's 55mm for his 7ii is also unbelievable. You need to have it checked out.

TMY-2 Rodinal 1+50 by carter3john, on Flickr

 

[RFH]

After a bit of research I guess it may be a question of a decentered element or a field curvature issue. I've requested a diagnosis and a repair quote from a place in the UK. Also there's a good chance I can work out a solution with the previous owner.

 

[RFH]

So... it took a while to get the lens back from the workshop. The bad news is that according to the repairman there's nothing formally wrong with the lens. He says it's not damaged, and the focus adjustment is correct. In his words: "It just doesn't get any better or worse".

The last roll I put through the camera seems to confirm his statement. The center is sharp, but the corners and edges are blurry.

No conclusion or solution at this time.

 

[Moto-Uno]

Is there a possibility that you're not applying enough pressure on the feed roll when you are pulling the beginning of the film through the take up spool ? Peter

 

[seblock]

Hello folks!

RFH, is there any new info about your lens?

 

[RFH]

Hi Seblock,


Sorry to hear about your issues with the lens. Strange that we have the same problem with it. Your photos show the exact same pattern of unsharpness as mine.

And no, it's not a film flatness or scanner issue. I checked side-by-side with the 80mm on the same film.

Just an hour ago I returned the Mamiya 7 + lenses to the guy I traded with, and got my Mamiya 6 kit back. Thursday I bought another 7 body with a 65mm from a well-reputed local camera shop, who just happened to have it the window display as I passed by. Will develop my first roll soon and see if the lens is okay. Crossing fingers.

When researching where to have the 'old' 65mm fixed, I came across Protech in the UK. They apparently know the Mamiya system well, and they have a spare Mamiya 7 body to test with, so you won't have to send yours in along with the lens. From seeing my negative scans, their guess was a wrongly adjusted or decentered lens element. Their price quote was very reasonable, appx. £50.
But, like I wrote, I opted for a local repair service instead.

Even though I don't have the faulty lens anymore, I'd still like to hear the explanation and solution to the problem, if you get one. Best of luck.

 

[RFH]

My first roll of Tmax 100 through the 'new' Mamiya 7 with the 65mm lens yielded good results.
I suppose this is how it's meant to look:

 

[swatch]

sorry to hear a few members having the issue with their 65mm lenses ... and hope solution can be found.

I've been putting my 65mm lenses on sales in this forum a few weeks ago and please drop me a note should anyone is interested

 

[Rob-F]

The only issue I know of with the 65mm is that there is an internal coupling device--I think it's a cable of some sort--which, while present in all the 7 and 7II lenses, fails more often in the 65mm. Nothing happens when you press the shutter release. I've had to return three of them for this problem. The focus issue has to be due to a problem, such as incorrect assembly, with this particular lens.