Reversible Lens Hood For Pany 20/1.7?

Started Feb 15, 2014 | Discussions thread
tt321
tt321 Forum Pro • Posts: 12,672
Re: Reversible Lens Hood For Pany 20/1.7?

Sean Nelson wrote:

Anders W wrote:

Sean Nelson wrote:

Anders W wrote:

...and doesn't interfere with the special "parking maneuver" of the 20.

I have the 20mm f/1.7, so I've just gotta ask what this "special parking maneuver" is...

Do what Bob already suggested: turn the camera on/off or mount/dismount the lens and look at the tip of the lens barrel. As you'll see, it will perform a little in-out dance (presumably a sort of AF self-test) during which it temporarily retracts the inner barrel so that it is slightly inside the outer barrel. If you have something mounted at the tip of the inner barrel, such as a step-up ring or a hood, that blocks that movement, it might not be so good.

That's what people worry about with regard to hoods (in this thread) and step-up rings (in others). With regard to hoods, I don't think there is any problem in most cases (although exceptions might exist). When it comes to step-up rings, you may have more reason to watch out.

That's very interesting, thanks guys!

I actually do use a 46mm to 49mm step-up ring on my lens to give me a common filter size with my compact camera filter adapter. And it looks like the "parked" position does want to retract the lens a little further than the ring will allow it to - if I power the camera off and screw on the step-up ring, then power the camera on and set it to manual "beyond infinity" focus then the ring is a bit loose and needs about 1/8 more turn to tighten it up. I can see a bit of a gap between the ring and lens barrel at that point, and no further tightening is needed when focusing closer, so it appears that the ring doesn't interfere with the "beyond infinity" focus point, only with the "parked" position.

I've been using the lens this way for several months now and have seen no ill effects, so I don't think I'm going to loose any sleep over it. Maybe it was a good thing I didn't know about this earlier!

There is either some permanent tension, or the ring is loose. I prefer the second choice. However, have a look at this:

http://www.amazon.co.uk/Cokin-Extn-Ring-46mm-R4646-A312/dp/B00009R7B5

Peace of mind for me now

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