Mamiya-Sekor Z Macro f4.5 140mm M/L-A

[iangreenhalgh1]

Mamiya-Sekor Z Macro f4.5 140mm M/L-A



This beast has an MSRP of $1900 and still fetches $300 or more on ebay, dependent on condition.

The last of the three versions oi the Mamiya 140mm macro, a very highly regarded lens, not just for macro work but for portraits, landscape, just about any use.

I bought this a while back incredibly cheap because the shutter had issues and there were some spots of 'fungus'. Well, I can't find this 'fungus' all I found was a bit of dust and so after a quick clean, the glass is perfect, pristine in fact.

Like all Mamiya RB/RZ lenses it's huge and very heavy - this one weighs 930 g. So I decided to take the optical blocks out of it and remount them.

I hoped that it would use standard sized threads like older Mamiya and Bronica MF lenses do, so it would be a simple task to screw the blocks into a Schneider barrel - Schneider barrels for enlarging, large format and process lenses come in the standard 0, 1, 2, 3 sizes that Compur and Copal shutters use, but sadly, this Mamiya doesn't, maybe the fact it uses a Seiko shutter should have been a clue. The blocks are slightly too big to fit a #1 barrel I have and are smaller than a #3 (#2 is virtually never seen in modern equipment).

As this lens has a floating element to ensure edge sharpness for flat field work, the rear block is in two parts, one stays stationary, the other moves. Obviously, when I have remounted it, it will no longer have a floating element.

But not to be deterred, I dug a beautiful barrel out of my parts box that used to hold a Wray Lustrar LF lens which has a 14 bladed iris that opens large enough to accommodate the Mamiya optical blocks.

BTW, you really don't want to know what I had to do to get the blocks out of the Mamiya barrel, it involved hacksaws, hammers, pry bars, monkey wrenches, a large vice and lots of swearing.

[Olivier]

Hi Ian.

I imagine the efforts, sweat and tears.
Am I wrong saying it's equivalent to a 90mm lens in 135 format ?

Did you manage to take some shots with your Mamiya beast ?

[iangreenhalgh1]

Bonjour mon ami!

It remains a 140mm lens on 35mm/FF format, just the outer portion of the image circle will not be used.

I haven't taken any pictures with it yet, the size and weight made it very very difficult to mount, I will take pictures with it as soon as the remounting job is done, which shouldn't be long.

[Olivier]

[iangreenhalgh1]

Merci beaucoup!

The lens was originally for a 6x7cm frame, which by my maths is a 92.2mm image circle.

If memory serves me correctly, FF has a 43.2mm image circle so I guess the crop factor is 92.2/43.2 = 2.13

I have already pretty much finished fitted the lens blocks into the barrel with aperture, now I just have to fit a helicoid and get the distance from sensor right.

Photos of the remounting to follow this evening.

[Olivier]

Bon courage !

[dan_]

[iangreenhalgh1]

I'm sure my job will be a lot less sophisticated than what you did Dan, but as long as it works...

Here's the parts before I started putting them together.

[Olivier]

I like puzzles...