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06-17-2014, 01:32 AM   #46
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good news

06-17-2014, 06:36 AM   #47
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QuoteOriginally posted by audiobomber Quote
A 25mm tube with a 100mm 1:1 macro lens only gives me 1.2:1, less than a 1.4x convertor and considerably less than a Raynox 250 (approximately 3:1).
Ah, audiobomber, I rather doubt you get 3:1 by using just a Raynox DCR-250 with a 1:1, 100mm macro lens. On my Tamron 90mm (272E), also a 1:1 macro, I get, with the Raynox 250, a 13.5mm wide image at minimum focus, for a roughly 1.7:1 macro ratio. Only with a 2x teleconverter, the Tamron and the Raynox 250 can I cross 3:1 - I get a 7mm wide frame at MFD, for a 3.4:1 macro ratio on the 23.7mm wide Pentax APS-C sensor. Perhaps you're talking about the Raynox MSN-202?
06-18-2014, 01:06 PM - 1 Like   #48
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Just recieved the 25mm extension tube from srb. I'll take it out in anger tomorrow with a few lenses and report back (most of my lenses are sat in my office at work sadly).

Initial impressions are a bit mixed. Mounting the tube is not a lot of fun (the manufacturing tolerances on the mounts could certainly be improved). Once it's mounted, it does do what it says on the tin.

I'm a bit limited with my lens selection at the moment, but I can safely say it doesn't work with the da 15mm - the focus point is pretty much on the surface of the front lens element! The da 21 is fine with it though (you get about 1-1.5 cm clearance), and the images all look good.

As I say though, I'll do some sensible tests with the da 40, da 50, and fa 77 tomorrow, and report back with some images...
06-18-2014, 01:37 PM   #49
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QuoteOriginally posted by Doundounba Quote
Ah, audiobomber, I rather doubt you get 3:1 by using just a Raynox DCR-250 with a 1:1, 100mm macro lens.
Sorry, you're right, My memory is crap. I just tested, it is exactly 2:1.

06-18-2014, 06:51 PM   #50
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I would like to see what the 50-135 would become with this
06-19-2014, 08:25 PM   #51
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My Q tubes are on the way. I am very, very excited to see how these work out.
06-23-2014, 08:19 AM   #52
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QuoteOriginally posted by audiobomber Quote
Sorry, you're right, My memory is crap. I just tested, it is exactly 2:1.
No biggie about your memory. What's interesting, though, is that you get a full 2:1 whereas my Tamron 90mm gets "only" 1.7:1. I wouldn't have thought there'd be such a difference. I think maybe it reflects on something I read to the effect that the Tamron's focal length decreases near minimum focus...? Might make it more suited to extension I guess. Now you have me tempted to get a 100mm (or a 105mm)...
06-23-2014, 01:38 PM - 1 Like   #53
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So I've returned the tube (the 25mm k-mount tube that is). It's crap, and not worth the money. Mounting this to your camera is an experience that none of you will enjoy. It's well made except it the one area it needs to be - the mount. My advice is to give it a wide birth. I'd intended to test it with four lenses, but was unable to mount a single lens in a two hour period.

I should probably clarify. Mounting the lens to the tube is straight forward enough (well, it's not fun, but can be done once you get the hang of it), but mounting the tube to the camera simply doesn't work. I could take the shots without the tube attached, but then couldn't get the tube to mount to my k-5 for the all important tests. The mount is just crap - and that's the polite description. Insert many more expletives, and you'll understand the joy I had with the thing.


Last edited by robthebloke; 06-23-2014 at 02:07 PM.
06-23-2014, 06:43 PM   #54
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Oh well, I was hoping for a replacement of the out of production Kenko/Jessups tubes. It probably wouldn't be cost effective to graft the mounts from a TC with screw drive.

Thanks for taking one for the team.
06-23-2014, 11:34 PM   #55
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QuoteOriginally posted by robthebloke Quote
So I've returned the tube (the 25mm k-mount tube that is). It's crap, and not worth the money. Mounting this to your camera is an experience that none of you will enjoy. It's well made except it the one area it needs to be - the mount. My advice is to give it a wide birth.
Thanks for being the pioneer, and warning us about the (lack of) quality.
Did you let SRB Griturn know about the problem?
06-25-2014, 06:13 PM   #56
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QuoteOriginally posted by robthebloke Quote
So I've returned the tube (the 25mm k-mount tube that is). It's crap, and not worth the money. Mounting this to your camera is an experience that none of you will enjoy. It's well made except it the one area it needs to be - the mount. My advice is to give it a wide birth. I'd intended to test it with four lenses, but was unable to mount a single lens in a two hour period.

I should probably clarify. Mounting the lens to the tube is straight forward enough (well, it's not fun, but can be done once you get the hang of it), but mounting the tube to the camera simply doesn't work. I could take the shots without the tube attached, but then couldn't get the tube to mount to my k-5 for the all important tests. The mount is just crap - and that's the polite description. Insert many more expletives, and you'll understand the joy I had with the thing.
so you returned the tube instead of asking for a replacement ?!
06-26-2014, 04:18 AM   #57
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QuoteOriginally posted by robthebloke Quote
So I've returned the tube (the 25mm k-mount tube that is). It's crap, and not worth the money. Mounting this to your camera is an experience that none of you will enjoy. It's well made except it the one area it needs to be - the mount. My advice is to give it a wide birth. I'd intended to test it with four lenses, but was unable to mount a single lens in a two hour period.

I should probably clarify. Mounting the lens to the tube is straight forward enough (well, it's not fun, but can be done once you get the hang of it), but mounting the tube to the camera simply doesn't work. I could take the shots without the tube attached, but then couldn't get the tube to mount to my k-5 for the all important tests. The mount is just crap - and that's the polite description. Insert many more expletives, and you'll understand the joy I had with the thing.
That is not good. The mount is a very simple thing so they should get that right. Well, when it's rubish it's just rubish.
06-26-2014, 04:22 AM   #58
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I still dont understand why everyone is bashing on this based on only one dude's experience... and why was it returned and not asked for a replacement? It could have been just a bad copy? I wish to see another person experience with another copy of the tube, and not just kept complaining before seeing more reviews.
06-26-2014, 06:58 AM   #59
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QuoteOriginally posted by leungclj Quote
I still dont understand why everyone is bashing on this based on only one dude's experience... and why was it returned and not asked for a replacement? It could have been just a bad copy? I wish to see another person experience with another copy of the tube, and not just kept complaining before seeing more reviews.
I agree, this sounds like a tolerance issue. It is beyond belief that all PK tubes will have the same problem.

I just about sent my Turbo back because I couldn't mount it, but eventually I got it on and it's loosened up since then (I am not suggesting that robthebloke should have, or could have, forced it on). What I like though, is that unlike my Q adapters, my RJ Turbo has zero play. It is solidly locked in when mounted, no rocking when you try to move it.

Last edited by audiobomber; 06-26-2014 at 11:22 AM.
06-26-2014, 09:19 AM   #60
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maybe they sent him a Nikon mount by accident? (i.e. with a lot of "fiddling" you can get a Nikon lens to mount to a Pentax body)

Just an out of the box idea...

m
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