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05-30-2022, 09:18 AM   #1
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Stacking extension rings and teleconverters (P67II)

Hi all,

When using both an extension ring and a teleconverter, I assume the extension ring goes on the camera, and the tele converter on the lens?

Cheers
Peter

05-30-2022, 10:36 AM - 1 Like   #2
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I've never thought about that combination before. And it seems logical to have the lens + teleconverter + extension tube stack up on the camera. So I gave the combinations a try with my Pentax Extension tubes and 1.4X rear converter.

I tried both the lens + converter + extension tube and lens + extension tube + converter mounted to the camera. Both seem to focus sharply except I could focus closer with the lens + extension tube + converter combo. I have the folding hood that has a magnifying glass to help judge focus.

I hope that's helpful
05-30-2022, 10:52 AM   #3
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Indeed - thanks :-)
05-30-2022, 12:16 PM   #4
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This article photographs by Mark Chappell: macro lenses

claims the quality is better if extension ring is in the middle, with indeed a lower but usefull magnification...

05-30-2022, 01:49 PM - 1 Like   #5
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Just recall that the purpose of extension tubes is to move the lens farther away from the camera's sensor (see the illustration below). If you think of your TC as part of your lens (that's really how it is functioning), then it will be clear that the order should be (1) lens, (2) TC, (3) tubes.

05-30-2022, 03:39 PM   #6
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Aggie's above illustration's a good, if simple, explanation of the effect of both rings and TC's (and 'crop factor' too).

The difference is that TC's spread the light rays optically independent of body length with whatever advantages and decrements in IQ the combined lens formulas impose. With rings there's no 'optical intervention' -- for either better or worse -- for any specific application or lens combination.

With today's high mega-pixel sensors cropping must be part of the trial with due consideration for other unavoidable effects such as MFD, DOF, perspective angles, stand-off distance and available lighting constraints on exposure.

As always, the best answer is to try all options and choose the best results for your unique application. The best will almost always be that with the best optical result with the lens only -- especially if not doing >1:1 true macro.

My experience has been that the most critical factor for practical use of close-ups has been to optimize gear and exposure for maximum depth of field rather than for the greatest magnification.

Truth is, in field use my most useful 'macro' accessories over the years have been a set of quality diopter filters. They're economical and take very little pocket-space so they're always available when needed. Today, a compact LED lamp with a USB battery pack has been very useful.

Last edited by pacerr; 05-30-2022 at 04:07 PM.
05-30-2022, 04:04 PM   #7
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QuoteOriginally posted by AggieDad Quote
Just recall that the purpose of extension tubes is to move the lens farther away from the camera's sensor (see the illustration below). If you think of your TC as part of your lens (that's really how it is functioning), then it will be clear that the order should be (1) lens, (2) TC, (3) tubes.
Don,

What a great illustration of how extension tubes work. I'd never thought about it that way but your illustration all makes it perfect sense.

Regards

Chris

05-30-2022, 05:23 PM   #8
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Some old Medium format cameras required extension tubes to be mounted in a specific order otherwise the whole camera would physically lock up - Bronicas were well known for this. Fortunately the Pentax 67 is pretty forgiving in this regard, for the sake of keeping the setup stable on a tripod I'd mount the TC first and try to keep the center of mass as close to the focal plane as possible.
05-30-2022, 08:01 PM   #9
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QuoteOriginally posted by pacerr Quote
Aggie's above illustration's a good, if simple, explanation of the effect of both rings and TC's (and 'crop factor' too).
You are right. It is simplistic. But it is a clear illustration of the concept. And when I am giving my macro presentation, I have found that it is best to keep everything simple and try not to confuse them with too many facts.


QuoteOriginally posted by pacerr Quote
Truth is, in field use my most useful 'macro' accessories over the years have been a set of quality diopter filters. They're economical and take very little pocket-space so they're always available when needed.
Agreed. My two Raynox filters (M-150 & M-250) are always nearby. They have good quality, and the mounts that allow using them with a variety of lens diameters make them very handy.
06-02-2022, 05:38 PM   #10
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With some lenses, there is no choice in the configuration between TC and tube. For the 600 Takumar, the tube must be put on the lens and the converter on the camera body. The resulting shots turn our well, at least with the 1.4X converter.
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