OT: Zoomatar 180 f/1.3 with sample photo

[Will]

WOW~!

Not mind, but someone in Taiwan have one, and posted sample photos on chinese opera. JLW, would want one.

http://blog.xuite.net/fdchen/lenses/6766463

He mention the quality wide open is not great (what do you expect?), but the lens is able to capture the decisive moments.

That guy also own CZJ Spieglobjekitv 500 f/4 and 1000 f/6.3.

Enjoy

 

[Will]

and he also own a CZJ 50mm f/0.77

http://www.geocities.com/fdchen/PhotoEquipment/Jena50_0_77P.pdf

 

[Will]

here is his collection:

http://www.geocities.com/fdchen/PhotoEquipment/MyZeiss.htm

 

[Will]

and a Goerz 1780mm Artar http://www.geocities.com/fdchen/PhotoEquipment/Goerz1780_16Artar.pdf

 

[clarence]

It's been almost a year since I had to read Chinese. If anyone wants a translation, I could help. Of course, Will probably could, too.

Now here's a question: If one were to take a fast, normal lens, and mount it on lots of teleconverters, would the maximum aperture still be the same? Granted, it would have a much more limited focusing range compared to a purpose built 180mm lens, but would the speed still be there?

Clarence

 

[erikhaugsby]

Now here's a question: If one were to take a fast, normal lens, and mount it on lots of teleconverters, would the maximum aperture still be the same? Granted, it would have a much more limited focusing range compared to a purpose built 180mm lens, but would the speed still be there?

Clarence

No. Teleconverters multiply both the focal length and the aperature. e.g.: a 300mm f/2.8 with a 2X TC would become a 600mm lens with a relative aperature of f/5.6 (300*2=600; 2.8*2=5.6)

 

[clarence]

I knew there had to be a compromise somewhere. Thanks, Erik.

Clarence

 

[PeterL]

There are front-convertors who can do what you describe, though. You only lose a bit because there's more glass. I have an Olympus 1.7x that turns my 90/f2 into a 153/f2.x. It shows some vignetting, though, as it was designed to turn a 180mm into a 300mm. That's immediately the disadvantage: the front convertor is designed for a certain focal length. Also, the front convertor's front lens needs to be large enough to allow your widest f-stop (you can't get f2.0 at 200mm because the front lens is about 7cm).


Peter.

 

[payasam]

Peter's right about things mounted on the fronts of lenses. Converters for fixed lens RFs come to mind. Those for today's digicams are much the same. Erik's right about tele-converters doubling both focal length and the numerical value of aperture. I wish, Erik, that you (and too many others as well) would spell "aperture" correctly.