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05-08-2017, 01:30 AM   #16
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QuoteOriginally posted by Lowell Goudge Quote
it was more in the comparison of the 4 options, not single comments
Ok thanks!

10-01-2017, 07:04 PM - 1 Like   #17
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I thought it might be helpful to bump this thread with some visual examples.

I have taken some photos with my Sun f/2.5 28mm lens using a 10mm extension tube and with a Vivitar 1.5x teleconverter. It must be noted that the extension tube example was taken using my K110D Pentax dslr, and the TC shots were taken with Kodak Prof Portra 160 using a Pentax ESII camera body. So the viewer must keep in mind that some differences are due to being recorded either with digital sensor or with film emulsion. Also, 10mm of extension is quite a bit on a 28mm lens and leads to a much greater magnification than would a 1.5x tc on a lens that is not already especially close-focusing. What these methods have in common is that neither a 10mm extension tube nor a 1.5x TC steals a great deal of light, so either might be used in a circumstance where one didn't want to (or couldn't) use a much wider aperture or slower shutter speed.

Here is a shot of lilac blossoms using the Sun 28 + 10mm of extension:


[previously posted]

I find it very sharp in the plane of focus. It is also important to understand that the lens-to-subject distance is very reduced using this amount of extension on this 28mm lens, reduced to a very few inches. Using the TC (in the next examples) makes no noticeable change from the normal the lens-to subject distance.


Here are 4 examples using the 1.5 TC:









I definitely think the extension tube picture is sharper (even allowing for film grain in the other examples), but the iris example certainly shows some good sharpness in the depiction of the veins in the petals. In the branches of pink weigela blossoms, some of the gauziness is the result of the Portra film's lower contrast and saturation which seem to reduce the appearance of sharpness that is actually there. The fleabane daisy and gray tree frog shots seem less sharp, but certainly the frog wouldn't have stayed on the branch had I been using the extension tube and had to shove the lens only a few inches from his face!

I don't normally think of a wide angle lens, like a 28mm, as a logical choice for close-up or macro shooting, but it is useful to know how much flexibility one has if one is carrying a skinny extension tube and/or a TC,
10-09-2017, 10:49 PM - 1 Like   #18
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QuoteOriginally posted by Lowell Goudge Quote
Note, I am not promoting one version over another, and all of the devices mentioned are in the majority of cases devices applied to non macro lenses, but for most people starting out, a set of close up lenses is usually the first thing they try, and a bright viewfinder is a big advantage. But it is not everything, I agree.
As it happens with teleconverters, not all diopters are the same, and not all lenses work with them the same way.
Cheap single-element chinese diopters are crap. Achromatic doublets are another thing. Some recent ones are even multicoated!
A good achromat works wonders with a 1:2 90/105mm macro lens, allowing for a relatively quick way to go to 3:4 or even 1:1.
Some 1:2 macros were originally sold with a matching diopter lens that allowed lifesize reproduction ratio.
Some old high-quality achromats can still be found second hand for a reasonable price. They should work fine on a film-era "normal" lens.
The best diopter is a reversed camera lens. Those who own a couple of vintage primes, for example a 28mm and a 50/55mm, could try to experiment mounting one lens reversed in front of the other. All it's needed is a super cheap male-to-male adapter ring. Google for further details. It's an old technique that can still prove its worth, if properly used.

QuoteQuote:
The vivitar macro TC is a good option for what it does, but these are getting somewhat rare and are not always cheap. I have one and like the versatility of the focusing helix, but note my initial intent was not to recommend any one solution but to explain the technical differences, which no one had gotten right to this point in the thread.

I have tried virtually every macro form available, including an enlarger lens mounted on a bellows, extension tubes used with and without focusing helix, macro lenses, (50, 90, and 100mm) close up lenses, and even an oddball sigma 135 mm close focus lens with 2 focusing rings, one on the whole group, and one just to move the front element for close focus.

Each has uses, and drawbacks, and if you play on the used market, macro lenses are plentiful in manual focus, but depending on what you are actually doing, a close up lens is smaller lighter and pretty good for casual use, or if you want capability just in case.
Vivitar, Panagor and Kenko macro teleconverters are in practice very similar but they come in two versions. One has a floating group, the other has an helicoid that moves the entire teleconverter away from the camera.
I own one example of the latter, with 7 elements. It was made by Kenko but it's marked Vivitar, and has electrical contacts.
This kind of macro teleconverters were originally meant to be used with film-era kit primes, opening the doors of macro photography to every owner of a basic kit.
As suggested in other posts, it could make sense to hack a PKA 4-elements converter, removing the optics, and turning it into a modern extension tube that allows basic EXIF and P-TTL flash.
I have nice "auto" tubes and bellows from the film times, but with the crippled PK mount of modern Pentax DSLR cameras they must be used with the green button procedure, with no support for P-TTL flash. I have a cheap 2x PKA converter that would be a perfect candidate for this kind of surgery. A pity that all 4-elements converters aren't thick enough to provide a good extension...

A side note:
all the best enlarger objectives (and some short focal repro lenses) are a great solution for non-handheld macro.
As the very similar plasmats used for still life on large format, they should be used the normal way up to 1:1, and reversed for higher reproduction rates.
This applies to most optics. Unless a lens is perfectly symmetrical, or was made for micro use, over 1:1 it has to be used reversed.

The price/performance ratio of 6-elements enlarger lenses is impressive, and the cost of a very basic M42 bellows is very low, but I wouldn't suggest to use a bellows + enlarger lens in the field (not impossible but complicated).

All in all, it's good to have multiple low cost options to try macro before investing in a dedicated optic.
Btw, AF makes sense for "macro hunting" up to around 1:2. Close to lifesize, and beyond, it's way easier to set the reproduction ratio beforehand, and focus moving the camera back and forth.
I learned that way, and it has become second nature. High reproduction ratios call for the use of a tripod, better with a micrometric rail... but I guess I'm going off topic now

Cheers

Paolo

Last edited by cyberjunkie; 10-09-2017 at 11:02 PM.
10-10-2017, 06:43 AM   #19
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Paolo, I used use my Takumar 1.8/55 reversed on the front of my 2-touch Vivitar 3.8/75-205. Had to make my own adapter in those days. Got some great shots using the set up on a copy stand; unfortunately none are digitally scanned and postable. I used the Takumar's aperture ring, leaving the zoom wide open. If I needed a hood on the reversed Takumar, a short extension tube screwed on the front did the trick. Since my copy stand was actually the post and arm from an old enlarger, it's adjustments were pretty good for adjusting focus. I could do some additional fine tuning using the Vivitar's zoom ring.

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