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A little adventure of TV lens

pentacon6

New member
As the price of 16mm cine lenses are going sky high, I try to explore the alternative world of c mount lens for G1. There are several prime camera producers such as Canon, Fujifilm, Pentax (Cosmicar), etc, made some quality TV lenses. After a series of research, I monitored eBay for about a month to try my luck on some usable items and get 4 lenses so far.
The lens are list below:
1) Canon TV lens 25mm F1.4, most usable, cover 3:2 with little dark corner;
2) Navitron 75mm F1.3, cover whole sensor but unable to focus infinity;
3) Cosmicar 12.5mm F1.4, just barely screw in as the diameter of the rear threat is larger than the adapter;
4) Norita Kogaku 6mm F1.8, cover diameter 17mm, fisheye like, uable to focus


Canon 25mm F1.4 (Right bottom); Navitron 75mm F1.3 (Right top);
Cosmicar 12.5mm F1.4 (Left bottom) ; Norita Kogaku 6mm F1.8 (Right top)

From the info above, just Canon and Navitron are able to use on G1. Other two need some modification to trim the rear mount to fit into the adapter.
Let’s see the result



G1 25mm setting:


 

monza

Active member
I have the Cosmicar, it is possible to machine the rear of the mount for proper fit and infinity focus. These are sharp lenses but do not cover the sensor completely.
 

pentacon6

New member
Test sample of 25mm:
My experience of this lens is it is soft at wide open, getting sharp at f2.8.
Color is natural and close to the actual color. Just cost me $30


Apeture at F2


F1.4


F1.4


F2


100% crop



Canon TV 25mm f1.4. Night shot.


100% crop
 

pentacon6

New member
Navitron 75mm F1.3 is quite a good deal except it can't reach infinity as the rear part of the element penetrating too much into the mount. There is about 2mm extra long and blocked by the front part of the sensor. May be some carefully trimming to get shorter can make it reach infinity. However, if you are not going to get some long range shooting and use it as a middle range tele lens for protrait and macro work, it is still a present lens to make you happy.

Closest focus 1 meter. You may partially screw out for a shorter focus (if you dare and sun shine is good). You may buy it now on eBay for $59 + $11 shipping.

Setting as below, quite heavy of about 300g. It is really not easy to focus unless you use the magnifer in the EVF. Hand shake is easy. Be careful :toocool:





The coating is not quite obvious, even not comparable with Canon 25mm F1.4TV lens. But may be a Leica Hektor 73mm F1.9 killer. :D

Samples are coming!
 

pentacon6

New member
Navitron 75mm F1.3 sample
Dreamy Tomatos on my messy table:

F1.3 wide open


F2.8


F8 test of sharpness of using a shuttle cock


100% crop


F5.6 (off focus, in fact...the largest orange is not properly sharp.)


F4 (almost another off focus shot. Closest distance makes your body shake to cause problem of hand shake or change of distance. Oops...)


F2.8


F4


F4


Natural color, good sharpness and 150mm F1.3 equivalent. Overall Performace is good. You seldom find a lens with such a large apeture in the 35mm lens world. It is also with a relatively reasonable price comparing with the cine lens. But of course for usability, Canon 25mm is still unbeatable as a 50mm standard lens. The only weakness is the closest distance is just 50 cm.
 

pentacon6

New member
Canon 25mm F1.4 Handheld macro (half screwing to the mount)

F2 @ISO 400


Also a test of my handheld stablility. 1/3s......Jesus
 
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pentacon6

New member
I have the Cosmicar, it is possible to machine the rear of the mount for proper fit and infinity focus. These are sharp lenses but do not cover the sensor completely.
In fact, I know the result already from a flickr member. He told me no machine is needed but I think it is not the real case. I will send it to my
friend who is studying in college to trim it for me.

Full album of both setting and sample:
http://www.flickr.com/photos/[email protected]/sets/72157617046578209/
 
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