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12-29-2019, 11:02 AM - 1 Like   #16
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RE: balancing the lens. My original post above is past the editing time limit so I couldn't add this pic there. This is the latest plate I made for a 31A (actually one I sold). Note particularly the second support point positioned between the zoom and focus rings, made from some polycarbonate pieces. The plate itself is made from 1/8"th alu, two pieces rivetted together (this is the easiest way to inset the D-ring screw, one piece is drilled first) with a bit of plastic sheet spacer so that the 3/8"th UNC to 1/4" UNC adapters don't protrude.
I also created attachment holes for both the 1/4" and 3/8" positions on the lens tripod mount ring.
Cost was negligible, I used some recycled alu, few pence for the rivets, I get 10x D-ring screw and 1/4" unc adapter lots, equates to around 30p each.

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Last edited by marcusBMG; 01-02-2020 at 07:16 AM.
12-29-2019, 11:34 AM   #17
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Why could I not find this thread when I was looking for it? I bit the bullet a couple weeks ago and am eagerly awaiting my copy of this lens, which should be some time this week. Given what I am seeing here, I am glad I bit the bullet, though I will have to find a way to stabilize this lens for sure. Now I'm really excited!
12-29-2019, 01:47 PM   #18
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QuoteOriginally posted by Asgardian Quote
Why could I not find this thread when I was looking for it? I bit the bullet a couple weeks ago and am eagerly awaiting my copy of this lens, which should be some time this week. Given what I am seeing here, I am glad I bit the bullet, though I will have to find a way to stabilize this lens for sure. Now I'm really excited!
Did you look in the index.? It has a link to this thread.
12-29-2019, 06:39 PM   #19
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Could have been a simple as incorrect spelling or sticky fingers. Who knows. I'll post some shots once it arrives.

12-30-2019, 10:23 AM - 1 Like   #20
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QuoteOriginally posted by Asgardian Quote
Could have been a simple as incorrect spelling or sticky fingers. Who knows. I'll post some shots once it arrives.
Don't feel bad, I missed it too!

Some more pix... the last two are with the 140F 1.4x TC






01-01-2020, 09:40 PM - 2 Likes   #21
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My first day with the lens, and yes I will need to do something to stabilize it for sure as my keeper rate was very low - even on the tripod. Heavy is an understatement! My post processing program is having a hard time dealing with the fringing (though it was very sunny and I was shooting into the sun - it should be less noticeable with better lighting.) Here are first set of keepers from the lens tests.



and



and



No where near as nice as some of the other images here, but I think this lens will take a bit of practice to master - especially with the razor thin depth of field at the long end.

A question for those who have used the lens before. Mine came with the 'normal' 43mm filter installed in the lens (none of the others came with it). Has anyone tried shooting without the filter, and if so, are the results much different?

Thanks!
01-02-2020, 05:12 AM   #22
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QuoteOriginally posted by Asgardian Quote
My first day with the lens, and yes I will need to do something to stabilize it for sure as my keeper rate was very low - even on the tripod. Heavy is an understatement! My post processing program is having a hard time dealing with the fringing (though it was very sunny and I was shooting into the sun - it should be less noticeable with better lighting.)

No where near as nice as some of the other images here, but I think this lens will take a bit of practice to master - especially with the razor thin depth of field at the long end.

A question for those who have used the lens before. Mine came with the 'normal' 43mm filter installed in the lens (none of the others came with it). Has anyone tried shooting without the filter, and if so, are the results much different?

Thanks!
Fringe removal tools work well, as can be seen from my chickadee shot in the first few posts.

One thing I thought about, but have not tried, with respect to stability, is to use the accelerometers in a cell phone (or iPod) to measure the vibration of the lens on the tripod. I used in the past just the optical view finder and image stability as a qualitative measure, but I am sure it is possible to make quantitative measurements of the resulting vibration as well. My principle concern here is mirror and shutter induced vibration, considering the long adaptor plate necessary to get the mount at the center of gravity of the lens, it needs with a K7/K5 a 100mm long plate. (My K1 should help offset some of this)

---------- Post added 01-02-20 at 07:15 AM ----------

QuoteOriginally posted by Lowell Goudge Quote
one funny problem, posted in the 300mm+ club also but should be here



look closely in the middle



not sure the source of the reflection and it is very small, but.....
QuoteOriginally posted by WillH Quote
Couldn't find your post on the 300mm thread to review the responces. Any ideas? I'm wondering the anomaly is a reflection off the sensor?

Do you use a UV filter over the front lens?
After a long time and lot of reflection(pun intended) think what I had called reflection is just out of focus twig in the foreground
01-02-2020, 08:26 AM   #23
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QuoteOriginally posted by Asgardian Quote
My first day with the lens, and yes I will need to do something to stabilize it for sure as my keeper rate was very low - even on the tripod. Heavy is an understatement! My post processing program is having a hard time dealing with the fringing (though it was very sunny and I was shooting into the sun - it should be less noticeable with better lighting.) Here are first set of keepers from the lens tests.



and



and



No where near as nice as some of the other images here, but I think this lens will take a bit of practice to master - especially with the razor thin depth of field at the long end.

A question for those who have used the lens before. Mine came with the 'normal' 43mm filter installed in the lens (none of the others came with it). Has anyone tried shooting without the filter, and if so, are the results much different?

Thanks!
Pics are looking good! I shot ducks my first time out with the lens, too.

I have noticed no difference in the lens' performance with or without the rear filter. Unlike some of the other big lenses, I don't believe the rear filter is considered part of the optical path.

01-04-2020, 06:20 PM - 2 Likes   #24
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QuoteOriginally posted by luftfluss Quote
I have noticed no difference in the lens' performance with or without the rear filter. Unlike some of the other big lenses, I don't believe the rear filter is considered part of the optical path.
Thank you for that. I've ordered a long plate for under $10 that is now coming to me on a slow boat from China (literally) So I will be able to rig up something for better stabilization. Until then I will just play around a bit. I put this on my KS-2 today and was able to get a shot with light at a better angle. I think I'm going to like this lens once I master it:



Thanks for everyone's comments and feedback!
01-05-2020, 06:09 AM   #25
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Nice one. At it's best that's what the 31A can do.
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