Saturday, 8 May 2010

"Home made" hood for the Lumix 20mm f/1.7 pancake

The Panasonic Lumix 20mm f/1.7 pancake is a brilliant lens, but it does not come with a lens hood. Flare is not a big issue with this lens, but a lens hood is still good for protecting the front element. Some people use UV protection filters for the same effect, however, adding another glass layer will reduce the image quality to some degree.

One option is to get a cheap third party hood designed for the Leica Summilux lens, to screw into the front 46mm filter thread. However, this hood adds some bulk to the lens, making it less compact. The compactness is one of the desirable features of the Lumix 20mm pancake in the first place.

In an attempt to find a low profile hood that looks more like the hood for the Pentax 40mm f/2.8 pancake lens, I bought a cheap 46mm to 37mm step down ring. The ring is essentially a short cylinder with 46mm threads on the outside, and 37mm threads on the inside.

The ring is made out of light metal, and is extruded on the rear side to save some weight:


Step up and step down rings should be used with care with the Lumix 20mm pancake. When powering down, the lens retracts the front assembly slightly into the chassis, which will jam and possibly damage the focus mechanism if you attach a ring which is too wide. The following picture shows that this step down ring is not too wide, and can be safely used with the Lumix 20mm pancake lens:


Looking at hoods, you will note that they are usually ribbed and matte on the inside. This is to avoid having light reflected into the lens. Since the inside of the step down ring is threaded, it already has the right shape. However, the metal is still a bit shiny. To make it more matte, I applied some matte black enamel paint on the inside threads. Wanting to retain the stealthy look of the lens, I also painted the front and the side of the ring:


Here is the lens with the "home made" hood attached. This hood does not cause any additional vignetting.


You will probably want to have a front lens cap as well, and you can get a 37mm cap which fits into the front threads of the step down ring. Both the step down ring and the front lens cap can be found on various auction sites.



21 comments:

  1. Denne var ikke dum...smart ide!

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  2. Nice idea. However with a UV filter attached, I guess there would be some vigneting. In this case maybe a 46 to 43 mm step down ring would be OK (I couldn't find 46 to 40mm)

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  3. I find that using a filter increases the flare and decreases the contrast. However, some might say that a high quality filter is better.

    If you add a filter, I agree that there might be a chance for vignetting. But it's easy to check if there is any vignetting. Just take a picture of the sky with and without the filter/ring, and look for differences in the corners.

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  4. The 20mm is one of very few lenses that is not at all prone to lens flare. So in this case a lens hood simply is not needed. Why bother with one, making the lens less compact, when it does not add to image quality?

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  5. Great advice! I don't know why I did not think of it for my Samsung NX 30mm pancake: I've been struggling to find a good polarizer at a decente price, but after reading your post I realized I can just buy a step-up ring and use on of my 49mm/52mm polarizers. And have it work as a hood too.

    Thanks a lot!

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  6. Prone or not, all lenses will flare when things go wrong (or right if you want flare) Decreasing the risk of flaring even minimally makes sens to me

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  7. Var har du hittat denna ring?

    Nils

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    Replies
    1. Make a search for "step down ring 37mm 46mm" on Ebay.

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  8. B&H have a 46 to 35.5 mm step-down ring. Would it be OK, or will a ring like that cause vingeting?

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    1. The same 46-37mm ring works well on the Lumix G 14mm pancake also, even if it is wider. So I would guess that a 46-35.5mm step down rings works fine on the Lumix G 20mm pancake lens as well, since it has a more narrow field of view.

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  9. I have both 14mm and 20mm Lumix pancake lenses. Is it OK for either lens to fit the 46-37mm step-down ring and then a 37mm filter on top, instead of using just a 46mm filter? I could then use the same 37mm filters on the Zuiko kit lens for my Oly E-PL2.

    Thanks

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    1. I am pretty sure this will work with the Lumix 20mm lens.

      With the Lumix 14mm lens, though, I fear that attaching the filter to the step down ring might cause vignetting. This is because the 14mm lens has a quite wide field of view.

      Try it yourself! Take a picture of the sky without the filter mounted, and then with the filter mounted. Is there more vignetting with the filter mounted? (More dark corners?) If so, then you should avoid this combination.

      If the amount of vignetting is the same, then you can safely go ahead.

      My gut feeling is that the 14mm lens will have some vignetting with a filter mounted to the front of the step down ring, though.

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    2. using a filter AT THE END of the hood defeats the purpose of the hood itself (stray lights/reflection protection and higher contrast) so if you're using hood just for the protection - why not just use filter only?

      remember, you're exposing GLASS to outside world so it is the GLASS you need to protect/covered that counts filter as well...

      why hood then? And in my opinion, this hood is highly ineffective (compared to proper hood) when it comes to actual difference in picture quality (there is, with proper shielding hood)

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  10. This is such a great solution. Ordered a step-down ring the same night as I ordered my E-M5 and Panasonic 20mm and it finally arrived today. Just perfect. Looks like just enough protection for the front element and negligible size penalty.

    Pondering whether to get a "real" lens hood for when it rains, but this should probably do.

    Thanks for sharing this. Now I just have to find a source for nice feeling 37mm lens caps.

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    Replies
    1. Yes, the step down ring makes me feel safer when using the lens. And it still retains the compact form factor.

      I just ordered the 37mm lens caps from Ebay. They cost virtually nothing.

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  11. Great idea. I ordered 2 and 2 37mm lenscaps with a little cord to attach to the camera... The daily search for the lens cap can finally end!!!

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  12. Will this work?

    http://www.adorama.com/FLD4637.html

    I'm worried because you said, "Step up and step down rings should be used with care with the Lumix 20mm pancake. When powering down, the lens retracts the front assembly slightly into the chassis, which will jam and possibly damage the focus mechanism if you attach a ring which is too wide. The following picture shows that this step down ring is not too wide, and can be safely used with the Lumix 20mm pancake lens."

    Thanks!

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    Replies
    1. Yes, I think that ring will work. It looks like it does not have an excessive diameter beyond that of a 46mm filter ring. Hence, it will not jam the focus mechanism.

      Step up rings should generally be avoided, and some step down rings extend beyond width of a filter ring, and should likewise be avoided. But this one looks safe.

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  13. I used this method for my Panasonic 14mm. It does not solve the flare problem of the lens but helps protect it somewhat. The problem I have is that it is very hard to find slim 37mm lens caps. The Amazon one shown on this page makes the total size almost as long as the stock 14-42mm lens. Completely defeat the purpose of using the 14mm on my camera. I do sometimes use the slim 37mm cap from my 14-42mm Mark II but that means I have no cap for that lens.

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    Replies
    1. I agree that the slim step down ring is mostly good for protection. I haven't found any third party slim lens caps myself. So sorry, I cannot help you here. If you make a search on ebay for "37mm lens cap", then some come up which look fairly slim. You could try some of those?

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