Sony a200 Exakta mount conversion

[iangreenhalgh1]

Hi folks

I recently picked up a Sony a200 for 70ukp, fully working apart from Steady Shot which I would never use as I do almost all my shooting with a tripod. I'm not interested in Sony lenses, nasty cheap plasticky things with many having poor IQ judging by reports.

However, I do have a few very nice lenses in Exakta mount so an idea foremd in my brain - why not change the mount on the a200 to an Exakta one?

I unscrewed the metal ring of the Sony mount and was surprised/shocked to discover the main part of the mount with the lugs is nothing more than a cheap piece of black plastic.

So I removed this plastic piece and a metal shim underneath it then cut a piece of 1.5mm aluminium sheet and used the metal ring I removed as a template to shape it into a round form and drill holes for the six screws, lens release rod and AF drive shaft. Then I used the Exakta mount (taken from a broken Exa, cheers Atilla!) as a template to mark out a hole in the centre which I cut out. I attached the Exakta mount to my new adapter plate with epoxy and four M1.6 hex head bolts which should make for a very strong mount (which puts the original Sony plastic crap to shame!) and the aluminium plate when screwed into the original holes in now recessed about 3mm inside the mount hole due to the removal of the plastic ring and metal shim; this means the Exakta mount sits at the same distance from the body as the original mount did. The Sony register is 44.5mm and the Exakta one 44.7mm, I'm not sure of the precise register of my new mount but it does allow infinity with a CZJ Pancolar 1.8/50m when the weather improves I'll try it properly.

Tools used:

Hacksaw
Rat-tailed File
Hand Drill
Emery Paper
Small Philips screwdriver
2.5mm Allen key
Bench vice
Tea mug (for necessary refreshments during work!)

Materials used:

70mm square sheet of 1.5mm aluminium
Exakta mount from broken Exa
4x M1.6 hex-head bolts with washers and nuts
Epoxy adhesive

Took about 4 hours with a few tea/fag breaks, classic British shed engineering!

Cost: 1.95ukp for 10x M1.6 screws, the aluminium sheet was a piece of scrap my dad had lying around and the Exakta mount was very kindly supplied by Atilla.

Further work to be done when the parts arrive is the fitting of an AF confirm chip to the back of the aluminium plate (blob of epoxy will do that) and replacement of the useless Sony focus screen with a proper split-prism with microprism collar one.

Project costs:

a200 body - 70ukp
M1.6 bolts - 2ukp
Focus screen - 12ukp
AF confirm chip - 9ukp
TOTAL: 93ukp

I'm happy with that cost, and with the excellent Zeiss, Meyer and Steinheil optics I have in Exakta mount, IQ should be pretty good.

The Exakta ring fitted inside the Sony mount but obviously would sit too far from the sensor so the Sony mount has got to go:



Trying my adapter plate for fitting, this is before I drilled the four holes for the Exakta mount; you can see the plastic ring and shim I removed bottom right:



The completed mount conversion:

[Attila]

Congrats!!! This is a great conversion , unlike lens butchering! Excellent!

[iangreenhalgh1]

Somehow butchering a cheap plastic camera not designed to last more than a few years feels much less sacreligious than butchering an old lens made to last a long time!

[dragom]

Intelligent engineering. Congrats.

[eddieitman]

Congrats on a very clever conversion, looks neat, I dont think your assesment of Sony/Minolta lenses is very fair.
There where some amazing lenses produced
Minolta 35-70 Beercan 70-210 Beercan, 28-85 Beercan, 70-300 G lens, 70-400G lens, 135 STF, 28-135 Secret Handshake, 50mm F1.7,
and many more, agree that many lenses that minolta produced after the Beercan era where not that good and made of cheap plastic thats what happens when bean counters run a company rather than engineers

[iangreenhalgh1]

I agree, the old Minolta AF lenses were pretty good, I had the 70-210 beercan and 1.7/50 when I used to own a Minolta 7000AF; it was the modern Sony lenses I was referring to, according to what I read, Sony ditched the Minolta designs and the new ones are inferior.

Here is the a200 with Pancolar, for me this is a better incarnation of a Sony-Zeiss partnership than the actual one Sony struck to use the Zeiss name:

[ludoo]

Fantastic job!

[Arkku]

[rbelyell]

ian to my non mechanical mind what you did was amazing! even to conceive the idea is beyond me. kudos to you and cant wait to see the results.

btw, i had an original a100 that i used with legacy minolta lenses, and i found those lenses were both inexpensive, pretty well made, and yielded great results.

[iangreenhalgh1]

I understand where you're coming from Arkku, I did look at reviews of the DT 18-70 and 75-300 and thought they were pretty crap, especially the amount of CA and distortion and I didn't think they had sufficient resolution for the type of landscape work I do, the 18-70 results reminded me of the Canon 18-55 I had and that was a dog with loads of CA at all lengths upto f8 and less than great resolution. I suppose when comparing them to other modern zooms from the AF era they might not be that bad but comparing them to my collection of good prime MF lenses, well, they are canine fecal matter imho. Looking at images from the 18mm end of the 18-70 was not a pleasant experience, especially in comparison to my Tokina 3.5/17 which is much better in all regards. I handled a DT 18-70 a friend has and it's like a toy, all plastic, feels like a strong wind would blow it out of your hand.

Cheers Tony, I have to confess it wasn't wholly my idea, I saw the similar conversion exaklaus did with his Sigma SD9 and just stole his concept.

I've just bought an a100 for 61ukp and that has the same malady - non-working steady shot, I am going to convert the mount on that one and also remove the hot mirror so I can shoot IR and UV with it. Not sure what mount I'll put on that one, I might not bother and just put an M42 adapter on it as I have a nice set of M42 lenses.

Interestingly for Arkku, I reckon it is possible to convert one of these Sony SLRs to Fuji X-mount which is 43.5mm register. When you remove the Sony mount you gain about 3mm of space to put the new mount in. Minolta MD should also be possible as that's 43.5mm too. Just wish it was possible to put a Konica AR mount on one, I love my Hexanons!

In a year or two when the SLT cameras like the a33 and a55 are appearing dirt cheap secondhand I plan to get one, take out the pointless pellicle mirror (only needed for the AF system) and put an Exakta mount on it, that would be a pretty cool camera to have imho with it's nice EVF and main sensor live view.

[iangreenhalgh1]

BTW, just tred my Steinheil Auto Tele-Quinar 3.5/135 on the a200, it has the Exakta arm so I didn't know if it would fit but to the flash protrusion on the camera. Well, it does fit, just not in the correct orientation, but rotated 120 degrees so the arm is at about half four o'clock and the aperture scale at about half one, which isn't so bad, definitely useable.

I just bought this beautiful zebra Tessar for 11ukp and that has an arm too, so very pleased I won't have to remove the arm to make it fit.

[luisalegria]

Well done !

It looks like a very neat job.

Like Attila says, camera bodies these days are not designed to last for decades, so butchering them is no great waste.

[Jesito]

Congrats for such a nice job!.

I'm delighted with the simple and precise way you found to do it.
To me this is major surgery, I doubt I'd dare to do something similar.

Regards.
Jes.

[Arkku]

[iangreenhalgh1]

Cheers guys, I found this was a pretty simple job, it's even completely reversible as there was no surgery to the camera apart from removing the 6 screws holding the mount in place and the metal ring, plastic mount underneath and the metal shim under that. The work was really all in the creation of the aluminium adapter plate to reduce the diameter of the hole in the body to accept the Exakta mount, as thin aluminium is very easy to cut and file/grind it wasn't that hard, I used very basic tools, just a hacksaw, file and hand drill.

It would be much simpler to put on a mount of similar diameter, Exakta just happens to be quite a lot narrower, hence the need to fashion a plate to mount it to. One good side-effect is this mount is a hell of a lot stronger and more robust than the original Sony one with it's plastic lugs as it's all metal and is held in place with four bolts and epoxy adhesive.

I have done a fair bit of lens surgery to adapt them and I really don't like doing it, with some lenses it can be a simple job (PB mount Pentacons are very simple to do) but with some (like my torturous conversion of a Canon FL 2.5/35) it is very difficult and time consuming and destroys the value of the lens. With modern cameras being almost disposable and obsolete after a few years, I prefer to convert the camera as it's a much simpler job and your lenses retain their value.

I've got a nice set of German glass to fit this a200:

Meyer-Optik Orestegon 2.8/29
CZJ Tessar 2.8/50
CZJ Pancolar 1.8/50
Meyer-Optik Orestor 2.8/100
Meyer-Optik Primotar 3.5/135
Steinheil Auto Tele-Quinar 3.5/135
Meyer-Optik Orestegor 4/200

I've also got a Palinar 4/100 that is tiny and quite good and a Soligor 5.5/300 that is light for a 300 and pretty good too, they are both T mounts with Exakta mounts fitted.

Sometime when funds allow I'll add 20mm and 25mm Flektogons to that line-up, maybe a 35mm Flek too. To me, that is a much better set of optics than any Sony or Minolta zooms and not a piece of plastic among them!

[fuzzywuzzy]

I don't know much about Sony SLRs but the specs looks decent, great bargain and nice conversion.

Give those zebras a workout!

[iangreenhalgh1]

The a100 and a200 have the same sensor as the Nikon D200, supposed to be a good one, 10.1mp is ample, especially as I do a lot of image stitching.

This is the a100 I got for 60 quid, I am tempted to put a PB mount on it so I can use my PB mount Pentacons and my M42 Meyers via a PB-M42 adapter.

[IAZA]

great price fro A200, great conversion too.
Hard to find such cheap price here

[iangreenhalgh1]

There are loads of a100s and a200s on ebay UK for under 100ukp, if anyone wants one and the seller won't ship worldwide I'd be happy to relay. I'd also be willing to do a mount conversion on it too.

[std]

You can count me in for camera and mount conversion- Exakta is enough i still have some nice lenses in that mount.
Indeed most of the nice ones are UK only.
If you find reasonably priced one i would be happy to get one

[yinyangbt]

Great work , Ian ,congratulations !
You could get a good bussiness from that , before the NEX and adapters !

[dragom]

[iangreenhalgh1]

I wouldn't charge much for the conversion, most of the cost would be the parts, for Exakta conversion I'd have to get a broken camera or teleconverter or maybe an extension tube to take the mount from.

[petr22]

There is sometimes problem with broken stabilizer on Sony cameras - sensor is stuck off-center, and it work as shift lens. This problem is usually with dropped cameras.

As with Praktica bayonet conversion - I recommend to use Canon camera, only Canon to Praktica bayonet adapter is needed, no need to remove original bayonet. For Exacta bayonet - Sony is perfect choice.

[iangreenhalgh1]

Sadly the damn camera has stopped working, I was shooting some pics and it just suddenly made a wierd noise and died, now all it does is flash the red light next to CF slot.

Oh well, think I'll get another NEX and use the Exakta lenses with that.

Pretty annoying though.