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Old Lenses Found. Are they worth using?

notalent

notalent

Active Member
My lens budget is quite small but I'd be willing to do the extra work required to adapt other lenses as long as the results could be OK. Until now I have had only one lens, the Sigma 18-50mm DC kit lens.

But I found a box of dead Pentax cameras and some lenses.

Camera: Pentax MV1
Lens: SMC Pentax-M 1:1.7 50mm
Lens: Sears model 202 Multicoated 1:4.0 80-200mm (ca. 1982)

Camera: Pentax ZX-M
Lens: SMC Pentax-A 1:4-5.6 35-80mm

Would any of these lenses be worth the effort of adapting to the SD14. It would be nice to have a prime lens and a zoom, even if they would be manual operated. What adapters (if any) would be needed?

Thanks!
 
G

Guest .

Banned
Hi Notalent,

Although I am a great fan of using old lenses with my SIGMAs, the Pentax-K Adaptation is a thing which I do not reccomment all that much. :)

It is possible to adapt them to SIGMA-mount but you will have to destroy the lenses' aperture mechanism. An non-destructive adaptation is impossible.

The other thing is, that flange distance will not fit exactly! Pentax-K lenses then are too close to the cam's image sensor.

Thus you can overfocus infinity.

Just go the other way! Get yourself the Polish M42 adapter and then go for old M42 lens stuff. If you do not mind manual focussing and working your aperture manually, you can have finest image results for very little money.

I have good dozens of ancient old lenses. Many of them do an outstanding job with my SDs.

See you with nice Pictures

Klaus
 
notalent

notalent

Active Member
I might have access to a manual 50mm prime lens from an old canon SLR. Can those lenses be adapted?
 
G

Guest .

Banned
Hi NOTALENT,

If the 50mm Canon is the old CANON FD-mount, there is unfortunately no chance to have it adapted. Flange distance then is just 42.00mm.
Later CANON EF (EOS) lenses can be adapted exchanging their bajonetts with SIGMA bajonetts.

See you with nice pictures

Klaus
 
Steaphany

Steaphany

Well-Known Member
I found Wikipedia has a nice listing of lens mounts ordered by flange focal distance:

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If a specific lens' flange focal distance meets or exceeds 44mm, while not having any elements protruding sufficiently to interfere with the Sigma IR blocking filter, then you have a candidate for conversion.
 
notalent

notalent

Active Member
Thanks Klaus for the always great advice and answers.
Thankyou Steaphany for the informative Wiki link! (love your time lapse clouds, BTW. :) )
 
O

OyvindS

Well-Known Member
Further info

Hello notalent!

I think that most lenses would outperform the 18-50 kit lens (I have one, hardly ever use it)

You do not need an adaptor for your K lenses, but there are some issues worth mentioning.
The SA mount is physically a Pentax K mount, and electrically a Canon EF mount. Many K mount lenses will fit the SD14, but as Klaus says, you may have to hack of the lever. Check first what you can sell these lenses for before deciding.

Next, make sure that the rear of the lens do not protrude too far into the camera body when mounted. Some lenses may hit the dust protector.

As stated, the registration distance differs: SA 44mm, and Pentax K 45,6mm. This means that the K lens will be closer to the sensor than it should be. The result is as Klaus says, it focuses past infinity - but it also affects the closest focusing distance; beeing longer.
A solution would be (if you already have hacked off the lever) to ADD a 1,46mm spacer (and longer screws, obviously).

The Canon lens you mention is of particular interest if it is a EF mount lens. With some work, you can retain both AF and AA (if the lens have it, that is).
You get hold of a SA lens mount, and desolder the contacts. If I recall right, they should then be resoldered in the opposite order.
If it is a FD lens, you have two options
a) an optical adapter - loosing quality.
b) grinding off 2mm of the mounting boss.
[FONT=Tahoma,Verdana,Arial,Helvetica][SIZE=-1]See: http://[/SIZE][/FONT][FONT=Tahoma,Verdana,Arial,Helvetica][SIZE=-1]forums.dpreview.com[/SIZE][/FONT][FONT=Tahoma,Verdana,Arial,Helvetica][SIZE=-1]/forums/read.asp?forum=1027&messag e=27332858[/SIZE][/FONT]​

For more information about lens conversions, have a look at my Non Sigma Lens compendium at:
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And a near complete drawing:
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notalent said:
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Click to expand...

kind regards
Øyvind
 
N

netzuser

Banned
""""You get hold of a SA lens mount, and desolder the contacts. If I recall right, they should then be resoldered in the opposite order."""""

The sequence of the contacts is the same at EF and SA.
So resolder the contactblock 1:1
At some of the flatribboncables from the EF lens,the EF50mm 1.8 for example, the solderingeyes
are to small to fit the Sigma pins.Use a .8 or .75 mm drill to make them fit to the Sigma contacts.
But most of the cables need no modification,they can be soldered blunt.
Regards
Uwe
 
notalent

notalent

Active Member
OyvindS said:
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Click to expand...

Should that be 1,6 mm spacer, the difference between 44mm and 45,6mm?

I might actually try this on the manual prime lens since it seems the easiest. I just want to verify the spacer thickness.

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Click to expand...

Where can I find an SA mounting plate? Could I "borrow" it from the kit lens?

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Thanks Øyvind for the advice and the links!
 
O

OyvindS

Well-Known Member
re:

Hi

You are welcome.
Of course, you are right : 1.6mm should be shaved off.

And thanks Owe for the correction to the cable order.

Kit lens could be a good candidate for a SA plate.
You will probably need to make new holes.

Good luck.

kind regards
Øyvind
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N

netzuser

Banned
@ notalent,
as a guideline,set
SD9: 5,6
SD10: 2,8
SD14: 1,0
Those settings usually work fine and give good results.
At the lens you should set your desired aperture value
at the camera set A and the camera will calculate the shutter-time.
Regards
Uwe
 
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