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Old Apr 11, 2010, 7:33 AM   #1
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Default Old TC to Extension Tube

So been chomping at the bit, literally seconds away from buying a proper macro lens and I remembered mtngal and bigdawg talking about converting an old TC to an extension tube.

I remembered I had an old Tokina 2x teleconverter that I never used. It was a matched TC for a lens I never had, so figured I might as well give it a bash as an extension tube instead.

I never realised quite how much of an effect it would have, I was staggered that on some of my lenses the point of focus was literally touching the lens. It was well within the mount of the macro ring "flash" and I had to try it on all my lenses to work out which would be suitable. Best combination seems to be on my Pentax 28-105 so far. It's not pin sharp by any stretch of the imagination, but should work fine for what I will use it for.

Removing the insides cost me a screwdriver and a few teeth on my pliers (was screwed in really tight), but they are considerably less than the 300 I was going to spend on a lens.

Quick shot from me trying out the different lenses:



Not cropped, just resized, that's about 1 1/2 inches of my son's toy rhino. Can get a lot closer than that so the eye (1/3 inch) fills the frame, but it's not very sharp.

Will give this a try tomorrow, see if the weather is good and go for a walk at lunchtime. Going to see about a reverse ring as well, seen some unbelievable images taken with the old Pentax 28mm K lens (which I own)

Apologies for what is ultimately a useless post, just wanted to thank mtngal/bigdawg for the tutorials and advice they have given elsewhere.
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Old Apr 11, 2010, 8:44 AM   #2
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Hi Tach.,

That 25mm should be just about perfect for reversing ! From all the macro I've been reading of late 25 - 35 is the best range for this type of macro photography, long teles don't work as well. Focus will be an inch or two at most from the subject.

Look forward to seeing what you can get out of it !
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Old Apr 11, 2010, 8:48 AM   #3
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Hi Frog

Yeah that was the idea, I will give this tube a try tomorrow assuming the weather is good (and I can find something suitable to shoot, it's still too early for bugs and the nicer flowers) and look at getting a reversal ring some time in the week.

I am also looking forward to seeing what I can get out of it! doesn't seem brilliant for dragonfly's but should be great for flower and more docile bug photography.
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Old Apr 11, 2010, 9:29 AM   #4
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Well went in the garden and figured I could find something to take a photo of to test it, and while I was taking photo's of the weeds in my garden, I spotted a tiny little butterfly sheltering from the wind.

Sadly it wasn't a pretty butterfly, and I have now found that you get a really bad reflection of the aperture when outside, so this might be destined for the bin already. But anyway, here's some weeds and a boring butterfly.



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Old Apr 11, 2010, 4:13 PM   #5
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You are getting the hang of using it, no doubt. Looking at your dandelion, it looks like the lens is pretty low-contrast (which can work in your favor). You might want bracket your shots - both the first and second ones look a bit under-exposed. Try them with a +ev (.3 - 1 for instance) and see if that helps a bit. The butterfly looks better as far as exposure.

Using non-macro lenses for macro purposes shows up where the limitations are for the lens. You do get better results with prime lenses compared with most zoom lenses as normally they are sharper. But you are right, with a little post processing, you'll be able to get quite acceptable results with the lens you are using.
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Old Apr 11, 2010, 6:14 PM   #6
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The dandelion and butterfly were taken with a Pentax K 50mm, and it was pretty dismal today, so hard to get a good shot, most of them in A mode were reaching 1/6s with f2.0... so pushing the absolute limits of shake reduction, plus it was windy...

Hopefully the weather will be good tomorrow and I can go for a walk around lunchtime when the light is better.

Ordered a reverse ring, but it will take a week or so to get here (H.K. post) so will give this a bash for the time being, and will probably order the Tamron 90mm next week. I noticed the 50mm K lens was pretty soft last time I used it, so either needs a thorough clean or just doesn't work well on the K-7.

As I said in the above post though, I am getting terrible internal reflections with this tube, you can see the lens flare/reflection in the bottom left of the butterfly photo (I cropped it a bit so it's not as obvious) so may have to admit defeat with this project depending on what tomorrow brings.
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Old Apr 12, 2010, 5:39 AM   #7
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Some very interesting results with this project. Will be curious to see how it does on a sunnier day. Sure would be lots cheaper than a dedicated Macro lens.
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Old Apr 12, 2010, 10:05 AM   #8
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Hi mole

I went out for the walk at lunchtime, and there was literally nothing to use the macro lens on other than grass and a few daisies. They have decimated the vegetation around the lake (I think they were reinforcing the bank) so there was nothing for the bugs to sun themselves on. None of the flowers were out (other than the daisies and a few daffodils) so an uneventful trip. Still the weather was lovely, and I got some exercise.

Will leave it a few days, hopefully more flowers will open and more bugs hatch by the time my reverse ring arrives from H.K.

Kind of nipped my enthusiasm in the bud, might have to convince my other half that we really should take the nipper to Bristol Zoo so I can go into the butterfly house...
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