http://www.rangefinderforum.com/forums en Mon, 06 Sep 2010 17:06:55 GMT vBulletin 60 http://www.rangefinderforum.com/forums/themes/graphite/misc/rss.jpg http://www.rangefinderforum.com/forums http://www.rangefinderforum.com/forums/showthread.php?t=94742&goto=newpost Sun, 05 Sep 2010 06:33:39 GMT http://www.youtube.com/watch?v=X7_wL...eature=related

Cheers,

Juan ]]> Optics and Lenses - Juan Valdenebro http://www.rangefinderforum.com/forums/showthread.php?t=94742 http://www.rangefinderforum.com/forums/showthread.php?t=94674&goto=newpost Fri, 03 Sep 2010 14:05:50 GMT So I understand the advantages of faster lenses and why someone would want to own them, but why would one want a slower lens? I'm just a 'student' of photography, so I guess I don't mind asking a stupid question. Do slower lenses give a specific desired effect?

Searching through the thousands of posts here can be a bit daunting, so if this is already spelled out somewhere, or if you have a good link, I'd be happy to read it.

Thanks,

DB ]]> Optics and Lenses - dogbunny http://www.rangefinderforum.com/forums/showthread.php?t=94674 http://www.rangefinderforum.com/forums/showthread.php?t=94635&goto=newpost Thu, 02 Sep 2010 14:19:40 GMT Enough of the dreamy, swirly, flattery-girly, wide-open yumminess... SHOW ME YOUR CRAP BOKEH!!! Enough of the dreamy, swirly, flattery-girly, wide-open yumminess...


SHOW ME YOUR CRAP BOKEH!!! ]]> Optics and Lenses - freeranger http://www.rangefinderforum.com/forums/showthread.php?t=94635 http://www.rangefinderforum.com/forums/showthread.php?t=94618&goto=newpost Thu, 02 Sep 2010 04:45:29 GMT Hello Forum. I have been in a discussion with a friend about close up imaging with tubes and bellows. A question has arisen from that, and with... Hello Forum.

I have been in a discussion with a friend about close up imaging with tubes and bellows. A question has arisen from that, and with which I need some help.

It is my understanding that when extending a lens with tubes or bellows, that its light at the film plane falls off with extension in lock step with the inverse square law.

For example, suppose we have a 50mm lens set to its infinity setting. Its focal length is 50mm. Now suppose that we extend that with a bellows or tubes to include another 50mm, now totaling 100mm. Suppose also that the aperture of the lens stayed at what is marked as f4 on the lens barrel.

It is my understanding that while the physical diameter of the aperture remains constant, the effective aperture changes from f4 to f8, two stops. And the light available at the film plane (because of diverging transmitted light rays coming from the open aperture area of the lens) is one fourth as much. This, I understand, agrees with the inverse square law.

I have been told that in close up imaging, explaining the light at the film plane in terms of the inverse square law is wrong to do, and oversimplified. I'm puzzled as to what is wrong about the way I am thinking about it.

Doesn't the inverse square law apply between lens and film plane just as it applies outside the camera? What am I missing in this? :bang:

Thanks for your insight in this. ]]> Optics and Lenses - HankOsaurus http://www.rangefinderforum.com/forums/showthread.php?t=94618 http://www.rangefinderforum.com/forums/showthread.php?t=94545&goto=newpost Tue, 31 Aug 2010 15:52:58 GMT The good news: I finally found a reasonably priced Summar! More good news: The glass is fairly clean. The not-so good news: There is what I believe... The good news: I finally found a reasonably priced Summar!
More good news: The glass is fairly clean.
The not-so good news: There is what I believe to be separation towards the front element. It goes all the way around the glass to a width of about a quarter inch. I took some test shots with it, and I can live with the resulting image characteristics (photos are distinctively "glowy") but I wonder if the separation will continue. It's a 1937 copy, so I suppose this has been a slow process, but I wonder if it is like fungus and should be corrected as soon as possible. ]]> Optics and Lenses - dogberryjr http://www.rangefinderforum.com/forums/showthread.php?t=94545 http://www.rangefinderforum.com/forums/showthread.php?t=94520&goto=newpost Tue, 31 Aug 2010 00:19:42 GMT Strange title, perhaps...but here goes.
My wife doesn't care or know which lens was used to take photos except for maybe one. Whenever I use the Nikkor-S Millennium 50/1.4 she's able to visually differentiate photos taken with this lens from others I've used. Perhaps she's been accustomed to it's foreshortening perspective, colour fidelity, etc. or whatever...

Can you name another RF lens, where your audience might say, "hey this photo must have been shot using _____ lens, because it has this specific characteristic" ]]> Optics and Lenses - Zen-shooter http://www.rangefinderforum.com/forums/showthread.php?t=94520