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Lens with adjustable curvature, CA corr, anyone needs it?
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PostPosted: Tue Jan 16, 2018 7:23 pm    Post subject: Lens with adjustable curvature, CA corr, anyone needs it? Reply with quote
Hello.

Long time no post here, I hope you're all doing well. I'm not exactly sure, whenever my topic fits this department, so it can be moved into more apropriate one, if desired.

I've obtained some lens components and have built an interesting lens, it is 50mm F1.2 lens, which almost covers FF (some dark corners on FF), but can only be used on Mirrorless, like Sony A series and so on. What makes it interesting, that aside standard focus and aperture (which is 16 blade perfect circular, btw), I've added some more features. Lens has two more dials. Rotating one adjusts field curvature (in cost of introducing some extra haze to image) and adjusting 2nd one affects CA and bokeh swirl as well. (You can have more CA and less soft focus or vice versa). Currently, this lens is in very alpha stage and I have no plans to make it final, perfect build. For my experiments it is just fine right now. However, if someone is interested in it, I can build 2 or 3 of them with more manageable exterior and outlook. Due to extreme complexity, it can't be cheap, I estimate around $250 including shipping. The attached sample shows CA correction set to maximum and field curvature correction set to minimum. All at maximum open aperture. More samples will be provided later.



PostPosted: Wed Jan 17, 2018 8:45 am    Post subject: Reply with quote
Sounds good for me. I am very interested in more images!


PostPosted: Wed Jan 17, 2018 9:36 am    Post subject: Reply with quote
Minolta produced a couple of lenses with variable field curvature so there must be a use for them. Unfortunately they are very rare so I've not had a chance to play with one. Their 35mm shift lens with curvature control looked particularly intriguing.

I'm interested but like ZoneV would need to see more examples, including some showing the extremes of curvature possible...


PostPosted: Wed Jan 17, 2018 9:52 am    Post subject: Reply with quote
I'm interested! would like to see some images of the lens.


PostPosted: Wed Jan 17, 2018 1:54 pm    Post subject: Reply with quote
DConvert wrote:
Minolta produced a couple of lenses with variable field curvature so there must be a use for them.

The only "real" VFC lens produced by Minolta was the 2.8/24mm VFC. Obviously it wasn't a commercial success; otherwise we would have seen more VFC lenses.
The Minolta 2.8/35mm Shift (also with VFC) was bought usually because of its shift mechanism, not because it was VFC.


DConvert wrote:

Unfortunately they are very rare so I've not had a chance to play with one.

First, the VFC effect is not very dramatic, and second, the corner image quality isn't that good when using VFC, especially wide open. And stopped down the VFC effect is nearly invisible...


DConvert wrote:
Their 35mm shift lens with curvature control looked particularly intriguing.

As mentioned above, the VFC effect isn't very obvious even at f2.8, let alone at f11 (which you need when the Rokkor 2.8/35mm Shift is shifted). Canons approach (tilt/shift) is by fas more convincing and more useful in real world photography (foreground/background).

This doesn't mean that the lens proposed here in this therad isn't interesting. On the contrary, for education / explanation of phenomena like field curvature and CAs it's very interesting!

Stephan


PostPosted: Wed Jan 17, 2018 5:16 pm    Post subject: Reply with quote
WOW, I was not expecting such huge interest to my creation. I will definitely upload more samples, and I guess, for better demonstration of the features, video will be better, which will in real-time show, how settings change affects image.


PostPosted: Wed Jan 17, 2018 5:43 pm    Post subject: Reply with quote
I'm certainly looking forward to a video demonstrating this lens, a picture is worth a thousand words , video must be millions of words. Cool


PostPosted: Thu Jan 18, 2018 11:06 am    Post subject: Reply with quote
Interested, but need more pictures from and of the lens, a video might prove informative.
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