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04-14-2013, 05:42 PM   #1
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World's Smallest 400 f2.8 Lens?

The Q/06 lens/Sony 1.7XTC makes for a 420 f2.8 lens. The combo is pictured below.

Dale

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04-14-2013, 05:47 PM   #2
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That looks....interesting to say the least!
Show pics soon!
04-14-2013, 05:50 PM   #3
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Looks interesting. Would love some samples.
04-14-2013, 06:06 PM   #4
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Would love to see what it is capable of.

04-14-2013, 06:06 PM   #5
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Here is an example of the cat. It is difficult getting good focus because of the step up rings required. Lots of fun to try though.

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04-14-2013, 06:10 PM   #6
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That is way beyond my expectations. It looks to be on par with adapted lenses. Can the lens really handle all that weight without any wobbling?
04-14-2013, 06:26 PM   #7
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It is best hand held as it is a lot of weight.

Dale
04-14-2013, 08:10 PM   #8
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Hmm.. interesting. I don't think the Q is engineered to handle that much weight on the lens mount. You might want to reconsider.

04-15-2013, 12:01 AM   #9
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Sorry to break it to you, but a teleconverter reduces effective aperture because it increases focal length. With a 1.7x TC, you're reducing aperture by about 4/3 so that's a 400mm F4.5.
04-15-2013, 12:08 AM   #10
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QuoteOriginally posted by DDoram Quote
The Q/06 lens/Sony 1.7XTC makes for a 420 f2.8 lens. The combo is pictured below.
I can hear the plastic in the lens cracking just looking at it.

And today is a good day to argue on the internet, so I'm going to have to say no it doesn't. It makes a 75mm lens. I'm not sure what speed, but let's say f/2.8, the front element is more than big enough.

The point here is that lenses do not change based on what sensor you put behind them. You can talk about equivalence if you want, but not about actually being. (And if you talk about equivalence, I personally think you should do it for the f-stop too, but I'm in the considerable minority there. Which is of course a good sign I'm either right or crazy. (In this case it's that I'm right. You get a 420/16 equivalent lens.))

QuoteOriginally posted by top-quark Quote
Sorry to break it to you, but a teleconverter reduces effective aperture because it increases focal length. With a 1.7x TC, you're reducing aperture by about 4/3 so that's a 400mm F4.5.
This is wrong in another way. Front mounted teleconverters may affect the speed of the lens, but they don't have to. Trivial not-really-proof: Fast lenses can have small elements in them, and the old front element is now just another internal element.
04-15-2013, 04:45 AM   #11
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I wouldn't be too worried about the lens mount on the body, (it's steel, and well built) but I would be concerned about hanging that much weight off the front of the lens on the filter threads... You may end up ruining the focusing helicoid in your lens. They're kind of delicate on those little Q lenses, and they're plastic. I wouldn't risk it.

If you want a cheap super tele for your Q, I'd recommend a Pentax M f3.5 / 135mm tele. You can get one for $50 or less, they're very small, equivalent to a 756mm lens on the Q, image quality is pretty good, and most important, you won't ruin anything with it.

Last edited by GibbyTheMole; 04-15-2013 at 05:00 AM.
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