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12-30-2011, 04:44 PM   #1
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Anything wrong with using dirt cheap extension tubes?

Like these?

I didn't want to lay out serious cash for hollow tubes.

Cheers,
Bobbo :-)

12-30-2011, 04:51 PM   #2
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no glass, but just be sure the mount can hold the lens. Last thing you want to experience is that tube falling a part and drop your lens on the floor...

3 screws vs 4 or 5 or 6 screws on the mount, metal or plastic.
3 screws on this one?
12-30-2011, 05:02 PM   #3
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I got a set similar to that from Fotodiox. They were useless due to the internal reflection from the glossy black paint used. One of these days I'll get around to painting the insides with a matte black finish.
12-30-2011, 05:04 PM   #4
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IMO/often written of possibly large flare. E.g., look at recent post here.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/169611-problem...ml#post1757265

12-30-2011, 05:27 PM   #5
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Just beware of their limitations:

- No mechanical linkage: you need to close down the lens yourself for metering and for taking the photo. The light is already dim just by nature of the extension tubes so you need to open up the lens for focusing, and then close it down for metering and for taking the photo. The DoF is so thin that a slight move of the camera can result in blurry photo.

- Can't be used with lens without aperture ring (or the aperture is at the smallest).
12-30-2011, 05:38 PM   #6
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I've got a set like that. They work ok, but you are limited as SOldBear mentioned. I took a cheap 2x converter and removed the glass, still eats a little light, but I now have the auto contacts and aperture control. I plan to get another one and connect them together to give me about 50mm of tube.
12-30-2011, 05:52 PM   #7
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QuoteOriginally posted by SOldBear Quote
- No mechanical linkage: you need to close down the lens yourself for metering and for taking the photo. The light is already dim just by nature of the extension tubes so you need to open up the lens for focusing, and then close it down for metering and for taking the photo. The DoF is so thin that a slight move of the camera can result in blurry photo.

- Can't be used with lens without aperture ring (or the aperture is at the smallest).
Yep. I knew about those limitations, but thanks for the heads-up.

So... is there a set of cheap tubes that won't give me flare or let go of my lens?

Cheers,
Bobbo :-)
12-31-2011, 05:17 AM   #8
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Another thing worth considering with tubes like these (I have a set that looks much like them) is the great sadness you feel when trying to mount/unmount them from each other. They only have one set of K mounts, the rest is a very (very!) cheaply made screw mount. At least my set didn't have any flare problems though.

There have also been people who got their lens stuck on them because the tab for pulling in the locking pin fell off. I would recommend buying them only to see if this tube idea is something for you, not to actually use.

12-31-2011, 06:19 AM   #9
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So what are some affordable, halfway decent tubes that won't break the bank?

After seeing this thread I got the jones to try my hand at shooting bugs.

Last edited by GibbyTheMole; 12-31-2011 at 06:32 AM.
12-31-2011, 09:48 AM   #10
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QuoteOriginally posted by GibbyTheMole Quote
Like these?

I didn't want to lay out serious cash for hollow tubes.

Cheers,
Bobbo :-)
I think my tubes are like that. I use an FA 28-90 and M 50 with them and get nice results. I dont notice any diffraction or flare from poor internal light reflection.
To me, the inabilities of auto focus or program modes are not that much of an issue.

Last edited by Nowhere Matt; 12-31-2011 at 09:57 AM.
12-31-2011, 09:56 AM   #11
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QuoteOriginally posted by Nowhere Matt Quote
I think my tubes are like that. I use an FA 28-90 and M 50 with them and get nice results. I dont notice any diffraction or flare from poor internal light reflection.
To me,the ability of auto focus is not that much of an issue.
Maybe I'll give em a try, then. I was planning on using them mostly with the lens (a 28 or M-50) reversed, so any kind of aperture control / autofocus, etc. is out the window anyway.
12-31-2011, 10:36 AM   #12
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I got an old set made by Chinon with mechanical aperture control, no A contacts. The brand was overlooked on eBay but brand is not very important for tubes, and Chinon is actually a decent manufacturer. It probably means a couple of weeks looking at bad eBay auctions though, and resisting buying other stuff.
12-31-2011, 11:19 AM   #13
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I use only the cheapest no-linkage PK tubes and have had zero problems with any of the ~8 sets I've bought. I use them in both temporary and permanent setups. Permanent: I glue tube sections to some large weird lenses, to serve as mounts. Temporary: for all the usual extension purposes.

I've never *had* to spray matte black paint into the tubes, but I've done so with bellows, and it's no problem. A fault I *might* expect with cheap tubes is that the outer surfaces of the mount pieces might be slightly warped|bent, but I haven't found such yet. Light leakage should be easy to check: mount the tube and a tightly-capped lens, then take a longish exposure. If the frame isn't totally black, there's a leak.
12-31-2011, 12:25 PM   #14
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QuoteOriginally posted by GibbyTheMole Quote
Maybe I'll give em a try, then. I was planning on using them mostly with the lens (a 28 or M-50) reversed, so any kind of aperture control / autofocus, etc. is out the window anyway.
I think you will find most 28mm fixed lenses will have a very, very short distance to subject. I think I was standing right on top of subjects to get them in focus. So alive insects would be out of the question. Between 35 and 50 might be a better distance.
12-31-2011, 01:32 PM   #15
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QuoteOriginally posted by Nowhere Matt Quote
I think you will find most 28mm fixed lenses will have a very, very short distance to subject. I think I was standing right on top of subjects to get them in focus. So alive insects would be out of the question. Between 35 and 50 might be a better distance.
Thanks for the tip! I'll see if maybe I can't score some cheap decent tubes & see what happens.

Cheers & happy new year,
Bobbo :-)
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