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A simple Periskop brass lens with old timer effect
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PostPosted: Sat Mar 17, 2018 10:56 pm    Post subject: A simple Periskop brass lens with old timer effect Reply with quote

I've got a brass lens without diaphragm. Its physical lengh is about 12 cm, the focal lenght might be around 250-300 mm. And its optical design is really simple, only two thick glasses on the both sides of the lens tube. I do not remember the name of this design. Doublet is when two glasses are stuck together, without an air space in between, right?

Being sharp enough, the lens renders with strong and beautiful (to my taste) abberations, with a very visible halo on every object edge. This gives the images a clearly vintage look.

#1 Under the bright sun, contrast and colours are boosted, as in all other shots


#2 A shot taken away of the sun, contrast is pushed high


#3 Details are still kept behind halos


#4 In a rather poor light condition, the halo is not so much pronounced


#5 An indoor with artificial light


#6 And this is a technical illustration of how the lens works. On the contrary to well corrected lenses its sharpness and colour saturation are placed at slightly different focus distances. I mean the following, if I wish the best sharpness, I lose the depth of the colour (blue here), as compared to the next shot.


#7 I move further the focusing bellow and the (blue and black) colours get richer, while the shapness is lost. Does not that explain rather well the halos? That must be the case that light beams reach the sensor with different speed, right?


As for the origin of the lens, I presume it might come from a magic lantern, seen its simple construction. Otherwise it could be a very old plate camera lens. I will put some shots of the lens itself later and will be very curious to know your opinions.


Last edited by alex ph on Sun Mar 18, 2018 4:14 pm; edited 1 time in total


PostPosted: Sat Mar 17, 2018 11:25 pm    Post subject: Reply with quote

Thanks for sharing this!

I'm curious about the pic of the lens itself too Wink

Also, I am wondering if monochrome-conversions could increase the impact of some of above pictures. E.g. #3 gets very busy-looking in colour, with all the halo's everywhere. But the first looks great, like it's taken from a fantasy or historic movie from the earliest days of colour film.


PostPosted: Sun Mar 18, 2018 12:01 am    Post subject: Reply with quote

Thamk you for your feedback, Sjak! You are right, the lens rendres the best simple objects or those with large shapes. It does not seem to render well human faces under bright natural light, for the same strong halo effect.

Black-and-white conversion may improve the overall impression of shots charged with details, but at a cost of modifying the halo effect.

Here is a simple BW conversion of the #3


And this is a BW conversion after an HDR was applyed to a single shot


Tomorrow I will post a shot of the lens.


PostPosted: Sun Mar 18, 2018 12:43 am    Post subject: Reply with quote





Wish I could find a better version of this:

http://antiquecameras.net/images/kigslakelenses.pdf

steinheil periskop lens


PostPosted: Sun Mar 18, 2018 4:13 pm    Post subject: Reply with quote

Thank you for this scope of great info! Mine is definitely a Periskop one.


PostPosted: Sun Mar 18, 2018 5:06 pm    Post subject: Reply with quote

Here is the lens itself.

#1 The previous owner carefully put duct tape on the barrel. It looks old, seems to be done many years ago. The construction and the decoration of the lens makes think it was designed for a magic lantern. What is unusual for me, the upper side of the barrel has two screws, the inner actually used and the outer you may see on the shot. Is it for interchangeable upper lenses?


#2 The lens came in cute brass box, with some soft tissue inside. So, one may say it was "in original box". I ask myself if such enclosure was usual for magic lantern lenses.


#3 The lens disassembled showing its basic construction (with two positive meniscus). Earlier I was mistaken about the lens' physical lenght. It is 6.5 cm, and not 12 cm.


#4 What opposes to an idea of lens for a magic lantern is a slot designed for drop-in aperture disks. Could such a lens be made for plate camera?


#5 And here is the whole setup on NEX accomplished with extension rings and bellows


What do yu think on the origin of the lens?


PostPosted: Tue Jul 02, 2019 3:29 am    Post subject: Reply with quote

The same lens put on Sony A7. This brings it a little bit closer to a "normal" glass. I guess with a LF camera it could be quite a pleasant portrait lens.

#1


#2


#3


PostPosted: Tue Jul 02, 2019 4:13 pm    Post subject: Reply with quote

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