F-mount Adapter Design Defect - Light Leakage

Started Apr 5, 2010 | Discussions
mjohnston Regular Member • Posts: 195
F-mount Adapter Design Defect - Light Leakage

I have an F-mount adapter from Rainbowimaging with a ring for aperture selection. They're carrying a slightly different version now I think, but if you use an adapter (of any kind) you might want to inspect it for similar issues as the one I'm about to describe.

Every once in a while I'd notice a shot that had a strange sort of flare that affected almost the entire frame. At first I thought maybe it was some kind of lens flare caused by the sun on a lens that didn't have a hood. That is until I noticed it on the LCD screen while the lens cap was still on!

The first shot is what I saw in the LCD screen. The second is what it does to a photo, and the third is the culprit. Light leaks in under the lens locking pin mechanism. I've since carefully applied some black silicone caulk to block the light.

sean000 Veteran Member • Posts: 7,727
Re: F-mount Adapter Design Defect - Light Leakage

Interesting find. Thanks for posting it. I use an F mount adapter off eBay that works with both G and non-G lenses. So far I haven't noticed any problems Good thing you were able to fix it.

 sean000's gear list:sean000's gear list
Olympus E-M1 II Samyang 7.5mm F3.5 Fisheye Olympus 12-40mm F2.8 Pro Olympus 40-150mm F2.8 Pro Olympus OM-D E-M5 +6 more
OP mjohnston Regular Member • Posts: 195
Re: F-mount Adapter Design Defect - Light Leakage

So the caulk helped a lot but there's still some leakage around the seam - I can get a very similar exposure to the one described above (with lens cap on) now at 10 seconds where before it took 1 second. I think I may add an elastic band/collar around the seam.

Philip Veteran Member • Posts: 4,009
Re: F-mount Adapter Design Defect - Light Leakage

Sean:

Can you please give me a link to the adapter you are talking about?
--
Philip

fsmith Senior Member • Posts: 1,148
Re: F-mount Adapter Design Defect - Light Leakage

The whole adapter is poorly designed. Attach the adapter to a lens and take a flashlight and shine the light at the junction of the lens and adapter. Looking into the bottom of the adapter, you will see all the places where light enters. There will probably be a big rectangular spot where the lens release is as well as several other areas along the mounting plate itself. I gave up trying to patch them and sent it back.

Fran

sean000 Veteran Member • Posts: 7,727
Re: F-mount Adapter Design Defect - Light Leakage

Philip wrote:

Sean:

Can you please give me a link to the adapter you are talking about?
--
Philip

Search eBay for "Nikon G to m4/3 adapter" and look for seller Shamino123. Here is a link to one of the posts and a photo:

http://cgi.ebay.com/Nikon-G-Lenses-M4-3-M43-Adapter-fit-G1-GF1-GH1-E-P1-/150517821360?pt=Lens_Accessories&hash=item230b8fafb0#ht_1157wt_905

The inside of the adapter had very fine black dust that I guess was left over from the manufacturing. I wiped it out with a lint-free towel and some rubbing alcohol. I'm sure water would do as well but then you have to let it dry longer. I use it regularly with the 50mm f/1.8D, 10.5mm fisheye (G lens), Tamron 90mm f/2.8 macro, and Tokina 12-24mm f/4 (another G lens).

Aperture adjustment is not precise at all and you have to use A mode and watch your shutter speed change to figure out what f-stop you move to. I wish there was a way to lock the aperture control as well. I mostly use it with lenses that have an aperture ring, so it's not a huge deal. There may be better adapters but at least I haven't noticed any light leakage issues and the connections between adapter and camera and adapter and lens seem reasonably secure.

Sean

 sean000's gear list:sean000's gear list
Olympus E-M1 II Samyang 7.5mm F3.5 Fisheye Olympus 12-40mm F2.8 Pro Olympus 40-150mm F2.8 Pro Olympus OM-D E-M5 +6 more
Philip Veteran Member • Posts: 4,009
Re: F-mount Adapter Design Defect - Light Leakage

Sean:

Thank you.
--
Philip

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