Mamiya / Sekor Auto 55mm f1.8 Lens - M42 screw fit

melmount · Joined: 10 Feb 2017 Posts: 18 Location: UK

Hi,
I have been watching Mamiya / Sekor Auto 55mm f1.8 Lens - M42 screw fit on eBay with bidding opening at £30.00. I have seen that the
SX version in M42 mount does not fit with most M42 adapters. Is there any way such as markings to distinguish this lens from the similar lens
also in M42 mount which will fit on the with the M42 adapters. Hope someone can give me some pointers. Is this lens worth the price above that quoted.

https://www.ebay.co.uk/itm/Mamiya-Sekor-Auto-55mm-f1-8-Lens-M42-screw-fit/223226638808?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2661

Thanks,
Melmount

tb_a · Expire: 2019-08-28

The common problem with various M42 lenses without A/M switch is that the aperture pin on the bottom of the lens has to be pushed by the M42 adapter in order to enable the usage of the lens stopped down; i.e. at all apertures.
I didn't find a M42 adapter up to now which works with all of these lenses. Therefore I fix the aperture pin in the pushed condition with a drop of super glue (Loctite, etc.).
This works fine and such lenses are then usable on all kind of M42 adapters at all apertures.

Oldhand

walter g · Joined: 20 Feb 2010 Posts: 2463 Location: NC, USA

I have the all black non SX version. What I should of bought is the Chrome nose version, which is the better lens.
So if your looking at pics from the Mamiya Sekor 55mm f1.8 online, make sure you know which version the pics came from.

MMouse · Joined: 18 Apr 2018 Posts: 58

Just don't buy a lens with SX mention on the front ring. I think everything else is ok.

papasito · Joined: 09 Jan 2015 Posts: 1658

If you want to buy the mamiya 1,8/55 you can look for the last versión, optically the better.
The 6/5 scheme has the beso IQ.
You can find it in DTL o en SX lenses.
In DTL versión, look for the 3 elements in 3 groups in the frontal optic

Lloydy · Expire: 2022-01-01

I have two versions, I think the later one without the SX pin and a SX, that I either removed the pin - or ground it off with a Dremel ? I can't the lens at the moment to check.

melmount · Joined: 10 Feb 2017 Posts: 18 Location: UK

Thank you all for your valuable input, much appreciated. I made an offer of £30.00 which was accepted. It would appear that lens is not an SX as there was no mention of SX anywhere on the lens. I should have it in a few days and will how it works and performs. Again thanks to all who provided input.

walter g · Joined: 20 Feb 2010 Posts: 2463 Location: NC, USA

Oldhand · Posted: Thu Nov 22, 2018 12:35 am Post subject:

papasito · Joined: 09 Jan 2015 Posts: 1658

walter g

The chrome nose is a 6/4 formula lens, as you can see in the old Mamiya advertising of TL lenses.

papasito · Joined: 09 Jan 2015 Posts: 1658

Ernst Dinkla · Joined: 30 Nov 2016 Posts: 378

papasito · Joined: 09 Jan 2015 Posts: 1658

papasito · Joined: 09 Jan 2015 Posts: 1658

Ernst Dinkla · Joined: 30 Nov 2016 Posts: 378

Alun Thomas · Joined: 20 Aug 2018 Posts: 628 Location: New Zealand

Looking on ebay, there seems to be more than just 2 optical versions of the lens, possibly as many as 4.

I believe this is the earliest M42 version, with the IR dot at 5.6, this is the copy I have. Said to be be 6 lenses in 4 groups.

This, I think, is the next version, also M42. The IR dot is now closer to F4 than 5.6, this version is said to be 6 lenses in 5 groups.

Next, the ES version from the XTL series cameras. On this version the IR dot is before F4. This version is also said to be 6 lenses, 5 groups.

Finally, the SX series lens. Now the IR dot is closer to F8, this version is also said to be 6 lenses, 5 groups.

Does the fact that the IR dot has moved point to a different optical calculation each time, even if only for a change of glass type used for instance?

Oldhand · Posted: Mon Jul 22, 2019 7:09 am Post subject:

papasito · Joined: 09 Jan 2015 Posts: 1658

papasito · Joined: 09 Jan 2015 Posts: 1658

And a little thing
I have the Chrome nose and the SX
We can say the first and the last versions.
I can't see importante differences in the IQ.
only the contrast is strong in the SX versión, and IT's warmer too.

D1N0 · Joined: 07 Aug 2012 Posts: 2491

A got a version of this lens without SX printed on the name plate but it turned out to be SX anyway. Bummer.

Back:

Front:

Auto Mamiya Sekor 55mm 1:1.8 by The lens profile, on Flickr

Also it doesn't have the a/m switch. Apparently not all SX lenses are marked sx. The serial number of this lens is on the barrel instead of the name ring. maybe an easy way to recognize.

papasito · Joined: 09 Jan 2015 Posts: 1658

Mamiya M42 55/1,8, AFAIK are

1 TL versión (chrome nose)

With series number at the front ring

6 elements in 4 groups

Two sub versions

Two different DOF scales

With and w/o AM .

2 DTL version. All black

With and w/o AM Stitch

With and w/o series number in the front ring

Some people salid that the scheme is 6/4 but I

only saw 6/5 scheme copies

3 SX The lens always say SX in the front ring

6/5 scheme.

Oldhand · Posted: Thu Nov 28, 2019 12:46 am Post subject:

Lloydy · Expire: 2022-01-01

I have the 50 f2 SX lens with the lip removed in my 'for sale' box, it's a nice lens, just selling it because I have the 55 f1.8 which I like more.
There's a 50 f2.8 in the box as well.

D1N0 · Joined: 07 Aug 2012 Posts: 2491

The lens doesn't seem to have the SX pin, so it must be a version made for older DTL bodies when the MSX bodies were already on the market to save on production costs making two versions of the lens.