[cataseven]

Hi All,

Do I lose magnification or image quality (vignetting etc.) if I use D FA 100mm macro lens as primary (attached to body) and 43mm as a secondary (reversed)? Or in other words, Can I use a macro lens for coupling? Is it a must to use non macro lenses for coupling?

Thanks.

[pathdoc]

The whole point of coupling is that it gives you instant macro if you do not have a macro lens. Furthermore, it gives you magnification equal to the focal length of the primary lens (mounted on the camera) divided by that of the reversed lens. The highest I have ever gone is by reversing the DA15 on the FA135 or 9X magnification, very close to microphotography. No single conventional macro lens can do this - even with bellows, things can get awkward.

What's important is that the front elements of these lenses do not differ too much in size, so that it's easy to make the connection once you have the appropriate reversing ring for the primary.

The other thing is that the primary effect in altering aperture for depth of field belongs with the REVERSED lens. For this reason, the reversed lens should really be an FA or something earlier, so that it has an aperture ring. You can do it with a DA lens, as I did just for fun, but then you have to close the aperture down by working the aperture lever with your finger, and you can never be sure of exactly what aperture you have set.

So no, it doesn't matter at all which two lenses you use (apart from obvious potential size differences). It all depends on what you've got. In this case the FA43 is a good choice, as it has the aperture ring and shares a 49mm front thread with the 100, and you will get about 2.3X magnification. My FA135 has a 52mm front thread and I needed a 52-49mm stepdown ring, but this was not a significant jump and introduced no real problems.

[WPRESTO]

In a book about close-up photography, the author, a Nikon user, recommended using a non-macro lens as the primary, but his reasons were unstated. It may be that a macro lens has more elements than a non-macro of the same FL and maximum aperture, so adding a multiple lens reversed on front kicks up the number of lenses to a point where IQ suffers despite the quality of both lenses being used. However, it may only be that the specific Nikon macro he was using (105mm f2.8, a very highly regarded optic in all of its manifestations) did not work well with the bellows-Nikon he was mounting in reverse position.

I have had good results with a Pentax bellows lens reversed on a non-macro SMCA 200 f4, but I think that the Raynox units work as well or better, and are much more convenient to use.

[BrianR]

Try it, coupling rings are inexpensive. I've been happy with the quality of an a28/2.8 reversed on a dfa100mm macro. Probably not an ideal combo given the recessed front element of the dfa100, but the other standard hurdles ( tiny dof, finding the subject, minimizing shake, diffraction etc) all greatly outweigh any optics induced image quality problems.

Ps. It's worth trying both methods of stopping down, primary lens or the reversed one. In my case, I had the best results stopping the reversed 28mm down to f4 or f5.6. iirc, if I stopped the dfa100mm down, it vignettes pretty quick.

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Last edited by BrianR; 06-28-2017 at 07:38 AM.

[tscip22]

Great responses from all. Would you mind sharing what f stops do you use on the longer regular mounted lens? Any details would be great. I have recently obtained a 49mm reversing adaptor. Thanks in advance.

[leekil]

The whole point of coupling is that it gives you instant macro if you do not have a macro lens. Furthermore, it gives you magnification equal to the focal length of the primary lens (mounted on the camera) divided by that of the reversed lens.

What is the magnification if you are only using a reversed lens with a body mount?

[WPRESTO]

My post about which lens to stop down seems to have gotten lost, so I'll repost and hope I'm not duplicating.
The author of the book I mentioned in the previous post recommended always using the aperture on the primary lens, but other marcophotographers adamantly insist that IQ is better if you stop down the reversed lens. This suggests to me that neither system is intrinsically superior, but some lens combinations may work better with the prime lens stopped down, others with the reversed lens stopped down, so it is prudent to experiment with your combination.
For my part, using the SMCA 200 f4 plus reversed 100mm f4 bellows-Takumar, I always use the aperture ring on the 200mm (bellows lens wide open) because I use the rig primarily for small active subjects, and I want the lens to stop down then reopen to full aperture as fast as possible. Also, I usually use f16 for maximum DOF and a strobe for movement-stopping exposure time (both the subject's movement and my own). DOF is painfully shallow at 2X natural size, and any gain in DOF is worth more than a small loss of definition caused by diffraction.
ADVICE: When photographing at greater than 1:1, it is sometimes easier to move the subject than the camera. Set up camera + strobe on tripod or other rigid support; pre-determine a manually set exposure by experiment; cable release in right hand; hold subject in left hand and move it to frame and focus. Easiest to do inside where you can sit in a chair, camera on tripod or clamped to the edge of a table, left hand resting on table or beanbag on table top to move the subject. This method can be used in the field with the camera + strobe on a tripod and a monopod to help steady your left hand holding the specimen. Set up in deep shady spot so you can use strobe (if the sun is bright enough to allow a very short TV, chances are the images will have far too much contrast/dynamic range). Insects may be on a twig or leaf or flower that can be twisted and turned however necessary to get the requisite framing and focus. Trigger quickly with the right hand when the subject is anywhere near correct and take MANY shots. Shifting the subject forward-back a millimeter will completely change what is in focus. Moving the subject up-down, right-left four or five millimeters will ruin your framing. TAKE MANY SHOTS to get both the framing and focus you want.

AND DO NOT BE DISCOURAGED. Those of us who post deep macros regularly are commonly showing the best of 15 to 20 shots of that particular subject.

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Last edited by WPRESTO; 06-28-2017 at 12:56 PM.

[pathdoc]

What is the magnification if you are only using a reversed lens with a body mount?

Varies according to the lens and whether there are extension tubes into the bargain as well. Quoting a few examples from Carl Shipman's "How to Select and Use Pentax SLR Cameras" (1977 edition, covering MX and ME):

28mm f/3.5 without tubes: 1.90 With all auto extension tubes K, 3.90

35mm f/3.5 without tubes: 1.40 With all auto extension tubes K, 3.03

50mm f/1.4 without tubes: not given. With all auto extension tubes K, 1.89

100mm f/4 macro without tubes, not given. With all auto extension tubes K, 0.30 (because of the optical design, the lens node is actually relocated to a WORSE place when you reverse it).

(From table on page 89)

So basically, the best bang for the buck in reversed lens terms is had at shorter focal lengths. The issue there however is that the image to focal plane distances get shorter and shorter, and the amount of light you lose is horrific - the exposure factor with just the 28/3.5 reversed is 6.4, for example, rising to a whopping 20.5 when all the extension tubes are also in circuit; there is no getting something for nothing. May your tripod be ever steady and your subject be always still (or lit with flash).