Wides with concave front elements

ferider

ferider

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When I finally got to try a 28mm Summicron, it occured to me how similar it behaves to my VM 35/1.7 (except for obviously being a bit wider). Resolution and contrast, field curvature (the Ultron has a bit more than the Summicron), OOF rendering and flare resistance are similar. With a bit more research, I find it striking how related the designs of the following four lenses are:

ConcaveLenses-X2.jpg


Puts does point out that the 28 Summicron was derived from the 35 Summilux. I personally think there are some genes of the Konica-M 35/2 (top left) in all the above lenses.

Thoughts ? Any other wides with concave front elements that you know off ?

Thanks,

Roland.
 
The Ricoh GR 28/2.8 lens of the GR1, the G-Rokkor 28/3.5 of the Minolta TC-1, the CV 28/3.5, the new ZM Distagon 35/1.4, ...

The list goes on and on. Almost all these lenses are symmetrical retrofocus designs, which means they must deploy a convex front element in front of a convex one, be it biconcave (shown in the OP) or plano-concave. Even the Biogons do, the difference being they have meniscus front elements (still concave).
 
Yes, the Canon FD 35 lens is known as the Concave Front version with chrome rim. Users swear by it.
 
BTW the Minigon XL 38/4.5 of the lowly Lomo LC-A 120 also has a concave front element. The lens has only 5 elements in 4 groups - yet still manages to cover 6x6 with 90 degrees of viewing angle. Surprisingly, it doesn't vignettes like hell like we'd suppose it would!

Given the few elements used it's quite a mystery what magic they played with the lens design, as Lomo doesn't release lens diagrams. Most "simple" retrofocus ultrawides I know of have meniscus (convex in front, concave overall) front element.
 
I'm consistently impressed with my FD 35/2 concave with thorium. It's sharp across the frame from f2 and resolves impressively well on the modern 24mp sensor. I think it's sharper than the FDn 24/2.8, and I've got a 24"x36" print that sharply resolves tiny details (like flying birds and rain drops) that I didn't even know were there.

I also really like the OOF areas with the 35/2, and the floating element (which the above designs don't have, right?) allows for incredible close-focus sharpness.

DJK
 
raid said:
Yes, the Canon FD 35 lens is known as the Concave Front version with chrome rim. Users swear by it.
Click to expand...


Raid,
How does this B&H/CANON Concave Black ring, Thorium and Floating rear element compare to the chrome nose lens? They would appear to be identical except for the chrome filter ring.
By the way, I bought an LED lamp at IKEA for $10 and it cleared the Thorium brown cast in the lens.
Thanks for your help.
Wayne
60bea7f08c98a084d291f36d6dd949a3.jpg



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venchka said:
.....How does this B&H/CANON Concave Black ring, Thorium and Floating rear element compare to the chrome nose lens? They would appear to be identical except for the chrome filter ring. ......
Click to expand...

Optically, they are identical. The only difference is the coating used. The SSC is multi-coated, the SC (chrome nose) is single-coated.

Jim B.
 
Mackinaw said:
Optically, they are identical. The only difference is the coating used. The SSC is multi-coated, the SC (chrome nose) is single-coated.



Jim B.
Click to expand...


Thank you! I'm not sure why the Chrome Nose gets all of the attention.
I will enjoy my stealth version!
Wayne


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