Author Topic: IS setting for macro lenses (Read 880 times)

brachiopod · « **on:** October 26, 2009, 06:20:38 AM »

OK, here is a hard one. At least for me

I have an old Pentax Takumar 50/4 lens that I'm using for macros. It seems obvious to me that at maximum "bellows" I get a lot more image motion than I would at 50mm. What should I set the IS focal length on the E-P1 to for this situation? Especially handheld, I need some IS on these macro shots. Is it 4X the focal length for this lens?

Olof in Amsterdam · « **Reply #1 on:** October 26, 2009, 04:46:56 PM »

I am not an expert, but the following seems logical to me:

Measure the difference in bellows length when focused at infinity and when focused at your planned distance. Add this difference to the focal length and use this total for IS.

Example:
bellows at infinity 83mm
bellows at 12cm 145mm
difference 62mm
focal length 50mm
Use 112mm for IS.

brachiopod · « **Reply #2 on:** October 26, 2009, 05:45:20 PM »

Quote from: Olof on October 26, 2009, 04:46:56 PM

I am not an expert, but the following seems logical to me:

Measure the difference in bellows length when focused at infinity and when focused at your planned distance. Add this difference to the focal length and use this total for IS.

Example:
bellows at infinity 83mm
bellows at 12cm 145mm
difference 62mm
focal length 50mm
Use 112mm for IS.

Oh, that's a very good idea.
It measures 56mm closed, and 108mm open. Assuming that the focal length is really 50mm as marked when closed (it focuses at infinity there), then it adds 52mm, so I'd use 100 or 105.

brachiopod · « **Reply #3 on:** October 26, 2009, 05:48:54 PM »

Here is how close you can get with it for example...

Olof in Amsterdam · « **Reply #4 on:** October 27, 2009, 04:13:41 PM »

Very Nice!

I guess it's 1:1 or even more.

brachiopod · « **Reply #5 on:** October 28, 2009, 08:24:35 AM »

Looks like it is pretty close to 1:1, I just shot a ruler at the closest and got 18mm across, and the mft sensor is supposed to be 17.3Ã—13.0, so It's close anyway. Hard to say if the focus was perfect, it is very difficult to hand hold at that distance. I had heard somewhere that this lens was actually just short of 1:1. There is a newer version of the lens that is only 1:2, this is the old one from the 1960's.

IS setting for macro lenses