Domiplan Revisited

[Sven]

In another thread we discussed the qualities of the Meyer Domiplan and the general opinion was not overwhelmingly positive.

For the fun of it I combined the Domiplan with another cheap item, namely my Soligor 2x TC just to see how bad it would get.
To my surprise I think it actually improved the performance. Bokeh got much better and I even think the shots came out a bit sharper (still quite soft though).
Judge for yourselves.

The rather strange looking combination



Domiplan + TC



Domiplan by itself



Reference shot with the SMC 2/50

[zewrak]

All I can say is, stick to the SMC

[Sven]

Yes, maybe it was a bit unfair to bring that shot into the comparison. Striking isn't it?

[Helios]

Most of "shorted" telephoto lenses (135mm) are of a similar formula relevant ... A triplet with a negative rear double element ... If you can experiment this, do it : you take off the rear element of a "shortened" 135 mm , then put the lens on an extension tube and what you get ? Almost the same 135 mm with a normal mount length ...
So the tc is like the "rear" element ... However , it is not exactly the same formula.
So triplet + tc is a theoric "not so bad" formula.

[Sven]

Interesting,
Thanks for the explanation about the optics. Thought that there could be some phenomena like that when I posted the thread.

[themoleman342]

That is extremely interesting! Now the Soligor TC is just a 3 or 4 element design that serves, like you say Helios, almost like a "rear" element. Would a better quality TC such as a 7 or 8 element design serve the same function or would it almost negate the odd "phenomena" and retain the domiplan's original qualities? Obviously it is just theoretical...but this is truly one of the most fascinating ideas I've seen.

[Helios]

Hmmmm ...It is not really true . The tc "negative" formula is more "powerful" than the similar (not identical, the optical register is not the same !) rear group of a "short" 135 mm .The 2 elements rear group of "shorterized" telephoto lenses are calculated for the triplet which is the basic formula of these lenses.
"normal" TC's are not dedicated to a particular lens formula , but they often give better results with a simple lens formula (achromatic doublet or triplets)
A six or seven elements modified gauss (1,4/50mm) with a seven elements TC can give a 14 elements 2,8/100mm horror ...