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05-11-2008, 08:57 AM   #16
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Here's a few very quick sample shots. All with K10D in manual mode:
First Vivitar 2x at full extension with an FA50mm/1.4. 1/6, f9, MF, ISO 400


Second the FA50mm/2.8 macro on it's own. 1/8, f9, MF, ISO400


Third the FA50mm/2.8 macro and Vivitar 2x at full extension. 0.6 sec, f5, MF ISO400. I think this has a touch of motion blur and could be sharper with a bit more light but the 2 together are tough to get a perfect focus only because the DOF is very small.


Last the FA50mm/2.8macro and Vivitar 2x both set as a 'prime'. 1/80, f9 MF ISO400


There was no cropping or retouching, just some resizing of the images to fit here. As you can see with careful use the Vivitar and a fast 50 can give similar results to the FA50mm/2.8 dedicated macro. I would suggest that an A SMC 50mm f1.4 or 1.7 would be the best lens to use. Simply because the focus ring on that lens is better than the FA50mm/1.4. I used the Vivitar at full extension and the FA50/1.4 was used to get focus ensuring the macro ratio was at 1:1. All these were taken with a tripod.

Finally here's a 100% crop of the 4th image. A bit soft but overall not bad for a TC. But there's no real highlights in the shot so CA/PF's are relatively well controlled. Shoot at a tree branch in the sky and you will delete the image much of the time.




Last edited by Peter Zack; 05-11-2008 at 01:19 PM.
05-11-2008, 12:13 PM   #17
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spanner in the works

QuoteOriginally posted by clm Quote
You can't not use it as a 2X teleconverter unless you have taken the glass out of it.
Just to throw a spanner in the works, has anybody considered taking the glass out of one of these units and turning it in to an "A" connected helicoid extension tube? Is this practical?

I just bought one of these from a fellow member on this forum, and am waiting for it to arrive. Ordinarily I would not use a 2x teleconverter, simply because of the added C/A, but I dont have any other way to increase the magnification of my macro lens without adding extra glass, or losing the "A" facility.

Am I being stupid? Probably

Last edited by keithlester; 05-11-2008 at 12:14 PM. Reason: to subscribe to the thread
05-11-2008, 01:02 PM   #18
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Not really. This is a workable idea. It would be great if you could take the lens assembly out with any damage and a way to re-install it if you wanted to. It would work just fine as far as I can tell. I don't know if the exposure info would be accurate as there will be light fall off inside the helicoid.
05-11-2008, 01:37 PM   #19
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QuoteOriginally posted by keithlester Quote
Just to throw a spanner in the works, has anybody considered taking the glass out of one of these units and turning it in to an "A" connected helicoid extension tube? Is this practical?

I just bought one of these from a fellow member on this forum, and am waiting for it to arrive. Ordinarily I would not use a 2x teleconverter, simply because of the added C/A, but I dont have any other way to increase the magnification of my macro lens without adding extra glass, or losing the "A" facility.

Am I being stupid? Probably
I've kind of considered doing this myself, but having been waiting to find a second copy for my surgery. My admittedly not-very-thorough efforts to see if the glass would easily come out of my copy did not reveal anything useful.

05-11-2008, 07:16 PM   #20
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QuoteOriginally posted by clm Quote
That is correct and that is what I am pointing out, but in your first post you said you never use it as a 2X. Read my first post carefully. I said "can't not," meaning you don't have a choice in whether you use it as a 2X or not, because that is what it is, regardless of whether the helicoid is extended or not.
You guys and your double negatives!
05-11-2008, 07:20 PM   #21
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QuoteOriginally posted by Peter Zack Quote
It would be great if you could take the lens assembly out with any damage and a way to re-install it if you wanted to.
I am pretty sure you can take the glass out, since I read somewhere on a different forum that someone did just that with a different teleconverter. All you need is a hollow tube and that gives you the extension.

However, getting the glass back in again? I don't think that would be a reasonable option.
05-11-2008, 07:35 PM   #22
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test of the V2XMFTC as a teleconverter

Here is my simple test of the V2XMFTC as a teleconverter, using the FA77mm wide open. The distance to the subject was 348cm. The top images are untouched straight out of the camera with a simple RAW conversion. The bottom images use my normal workflow, which includes sharpening. All are 100% crops.

The images on the left are with the FA77 alone. At ISO 200 the exposure was 1/250s at f/1.8. The images to the right are with the V2XMFTC attached. The shutter speed has changed to 1/60s which makes sense since that's two stops slower. The aperture has oddly enough morphed to f/1.7, marginally faster than before! This I do not understand.

To my untrained eye the doubling of the effective focal length does not seriously compromise the image. There is more purple fringing at first glance, but if one was to simply blow up the left image it would be just as bad. The resolution does suffer a little; the images on the right are not exactly as clear as those on the left. I also see a little contrast degradation? However, in this situation, with only a little back-lighting, I would not mind using the teleconverter if I needed the reach.

If anyone else has opinions on these shots, I'd be happy to hear them.
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05-11-2008, 07:36 PM   #23
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Ding! Ding!

Just clocked 500 posts.

05-13-2008, 03:12 PM   #24
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.


Mine works very well with the M 50 1.4 - gives me a 100mm f/2.8 1-1 macro! I have 3 actual 1-1 macro lenses now, though, so it doesn't really get used anymore.



.
05-26-2008, 06:59 PM   #25
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A thread on fixing the converter should the auto-aperture not be working is here.
05-26-2008, 06:59 PM   #26
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Ding! Ding!

600 posts!
05-26-2008, 09:51 PM   #27
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I guess i need to get my vivitar 2x macro focusing teleconverter out and try it with my new DA35mm macro? I'm betting it might be a 70mm "micro"
Levi
05-27-2008, 08:39 AM   #28
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You can't remove the optical assembly from the Viv. The assembly is attached to the rear lensmount.
05-27-2008, 11:03 AM   #29
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CAN'T eh?

QuoteOriginally posted by JMS Quote
You can't remove the optical assembly from the Viv. The assembly is attached to the rear lensmount.


Dont you just love that word, CAN'T.
Its almost a red rag to a bull.
The opposite of attached is detached, it just remains to be seen if I could remove it non-destructively. I think I'm gonna use it as it is for a whiley before I start chopping it to bits. But I never believe the word CAN'T
05-30-2008, 11:45 PM   #30
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Have been playing around with a old Richo 2x macro teleconverter I bought off Ebay for 25 and thought I would post a sample.
The first picture is with a standard 50mm F1/7 manual lens.
The second is with the teleconverter attached.(focus is just a tad off though)

Both are at maximum focus and neither picture is cropped in any way.

It actually does a pretty good job of turning a bulk standard lens into a 1:1 macro.









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