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07-24-2018, 01:39 PM   #1
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Modifying an M400/5.6

I have this lens, and I have a 1.4x-L converter that I bought for use with my K500/4.5. I've used other converters on the M400 but why do that when the L version is here? The answer is "incompatibility."

I noticed the only thing keeping the converter from sliding into the back end of the lens is a little metal spacer/baffle (see photo).

After several days of trying real hard not to strip the lens mount screws, I finally got it off (secret = apply heat, directly to screws, sometimes for a long time, maybe allowing a couple of heat/cool cycles, thanks for the advice Eric!) and removed the baffle. Once removed, the inner felt-lined barrel wants to spin, so I put the small screws back into the lens in such a way as to hold it steady, at least long enough to test if the thing will even focus.

So, here are some preliminary and fairly shabbily done results. I'll show the images in pairs in subsequent posts for comparison, but please note all I was trying to accomplish was to a) see if the lens would focus with the converter on, b) see if there were any ill effects of not having the baffle in there, and c) see what deleterious effects there are, if any, on the lens from the baffular absence.

First two images, wide open, infinity focus, 560mm on top.

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07-24-2018, 01:42 PM   #2
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Next two images, f/16, infinity focus. Unfortunately, I wasn't smart enough to use the construction site for all the infinity photos... maybe after subsequent modification, I'll do that.
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07-24-2018, 01:43 PM   #3
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Next, minimum focus distance, wide open.
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07-24-2018, 01:46 PM   #4
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And finally, a couple at minimum focus distance at f/16. Converters do not have an effect on minimum focus distance, just in case you did not know, and this was confirmed as I stood in the same spot for both of these photos.

Also, a photo of the round baffle thingy-madoodle that I removed to enable compatibility. Words on "issues" I encountered in the next post.

---------- Post added 24th Jul 2018 at 03:50 PM ----------

So, after removal of the round part, i discovered that the aperture mechanism sounds a little "loose" for lack of a better word. Also, if the lens is upside down (aperture numbers facing the floor, lens in horizontal position), the aperture will not close. I don't hear anything that sounds loose or free inside the lens at this time, but it seems clear the round-o was doing something more than just keeping the lens from being fully compatible with the really cool L extenders.

My curiosity is satisfied that the lens will perform well with the converter, and that the lens still performs fine without it, and without the added piece. The plan now is to modify the piece such that the straignt edges are curved enough to allow entry of the nose of the 1.4x-L. I guess that means I need to get a Dremel.

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07-24-2018, 02:48 PM - 1 Like   #5
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Gearhead response: Nice series and experiment. Of course you could just save yourself the trouble, and the risk to damage a very nice lens, and buy an A1.4x-S TC
07-24-2018, 03:13 PM - 1 Like   #6
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I suggest you 3d print one or have one machined rather than modify that ring.
07-24-2018, 04:12 PM   #7
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Hi monochrome! I've got an S version too, and I spent several nights cleaning it up and re-tuning it because it seemed to be crapping out at infinity. I don't think it was allowing infinity focus, but I think I've fixed it. I guess the real problem is that I got a set of screwdrivers and the oppressive heat just made me want to take something apart.

Uncle Vanya, I wouldn't have the first clue how to go about 3-D printing something like this. Got a tip?
07-24-2018, 04:16 PM - 1 Like   #8
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QuoteOriginally posted by jcdoss Quote
Hi monochrome! I've got an S version too, and I spent several nights cleaning it up and re-tuning it because it seemed to be crapping out at infinity. I don't think it was allowing infinity focus, but I think I've fixed it. I guess the real problem is that I got a set of screwdrivers and the oppressive heat just made me want to take something apart.

Uncle Vanya, I wouldn't have the first clue how to go about 3-D printing something like this. Got a tip?
Just jazzin ya Have fun!

07-24-2018, 05:27 PM   #9
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Cool post. Weird about the aperture upside down.
07-24-2018, 07:32 PM   #10
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QuoteOriginally posted by jcdoss Quote
Hi monochrome! I've got an S version too, and I spent several nights cleaning it up and re-tuning it because it seemed to be crapping out at infinity. I don't think it was allowing infinity focus, but I think I've fixed it. I guess the real problem is that I got a set of screwdrivers and the oppressive heat just made me want to take something apart.

Uncle Vanya, I wouldn't have the first clue how to go about 3-D printing something like this. Got a tip?
There are a number of places that will scan and print with a 3d printer, whatever you want. Search engines are your friend!
07-25-2018, 04:50 AM - 1 Like   #11
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QuoteOriginally posted by jcdoss:
Uncle Vanya, I wouldn't have the first clue how to go about 3-D printing something like this. Got a tip?
Look for a local "hacker space" and talk to the folks there.
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