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02-05-2015, 02:06 PM   #1
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Which ring for lens stacking / reverse (macro)?

I'm thinking now about playing a little with lens stacking or reverse mounting.


Just wondering which of my lenses would be the best option to start with.


One idea might be DFA-100 + reverse FA50 (or FA28?).
-> is this ring the right one which I need? 49 49 Male to Male Coupling Step Ring Adaptor 49mm Lens Filter Adapter Dual Male | eBay
Or would you recommend another combination of some of my lenses?


2nd option is then a reverse ring, something like this (?) - Asahi Pentax Umkehrring Reverse Ring 49 mm Pentax K PK Bajonett Mount 30332 | eBay


And again - which of my lenses would be most suitable for reverse mounting?

02-05-2015, 02:41 PM   #2
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I don't know, but I've got a 62 to 52 ring and tried to do something with a 105mm macro lens + reversed 50mm helios. In that combination the dof was incredible small. I have no experience, but focus stacking seems to be the only solution when using two lenses.
02-05-2015, 03:04 PM   #3
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I've found with stacking that what really matters is the optical quality of the secondary (i.e., reversed) lens. The primary lens is effectively stopped down so much by the secondary lens that any decent lens will do.

Beyond that, some questions are: what magnification do I want; what lenses are light enough for reversal without risking damage to filter threads; what lenses am I willing to expose the rear elements to the world.

How much magnification do you get with the Raynox 250 on the DFA 100? The Raynox is of such good quality that I wouldn't reverse lenses except for a magnification you can't cover with the Raynox.
02-05-2015, 04:44 PM   #4
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Personally, I generally use a Pentax-M 135mm or 150mm (49mm) as the primary, and I wanted to try secondaries that range from 49mm to 58mm in diameter, so I bought a 49mm to 49mm and a 49mm to 55mm, and then also a set of step up and down rings (something like this, not necessarily that exact one mind you, that's just the first search result I got just now). I then try to never use more than a single step up (or down) ring on top of the reverse adapter, to keep the secondary reasonably close to the primary. Using a reversed zoom as the secondary makes for a very convenient variable magnification extreme macro rig, though primes of course tend to produce sharper results, especially at the highest magnifications. In practical terms, that means I've had better results from 135mm (or 150mm) plus a reversed 24-70mm zoom at the long end of the zoom, and even in the middle of the range, than at the shortest end...

Looking at your lenses (from your sig), I'm not sure what to say. I agree with baro-nite that up to 2:1, I'd rather use a Raynox 250 on the 100mm macro - much more convenient shooting. Then maybe I'd try F 135mm plus reversed FA 50mm F/1.7. That would give you 2.7:1 and should be optically very good... And don't forget to stop down the reversed lens as much as possible. Then if you're feeling ambitious, try the 135mm plus a reversed 28mm.

BTW, it's quite possible to get decent results from single frames (without focus stacking) even at pretty high magnifications, but it's a very difficult quest. (Here is a link to a 6:1 single frame shot of a minuscule jumping spider.)


Last edited by Doundounba; 02-05-2015 at 05:03 PM. Reason: Hit "Post" too soon...!
02-05-2015, 05:46 PM   #5
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Yes, the first ring is the right one. If you have two lenses with 49mm filter thread.

I'd recommend 50mm in front of 100mm. Or 135mm. So the FA50mm+DFA100.

Oh yeah, even a poppyseed grain will look huge and like some kind of vulcanic bomb.
02-05-2015, 06:01 PM   #6
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QuoteOriginally posted by Doundounba Quote
And don't forget to stop down the reversed lens as much as possible.
One thing to keep in mind is that effective f-number depends on magnification, so stopping down at high magnifications makes diffraction softening very apparent. I admire your 6:1 shot of the jumping spider, but you could have captured a similar amount of detail at lower magnification and cropping the result. I find that 4:1 is about the useful limit when using SLR lenses, and that only with a particularly good secondary lens set to its optimum aperture. 3:1 is a more practicable limit. When I want to go higher than that I reach for a specialized bellows lens or a microscope objective. And at those magnifications stacking becomes mandatory.
02-05-2015, 07:53 PM   #7
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QuoteOriginally posted by baro-nite Quote
I admire your 6:1 shot of the jumping spider, but you could have captured a similar amount of detail at lower magnification and cropping the result.
Quite possible, but it would definitely not have been as much fun! Note that that one is F/8:F/13, so not actually that stopped down. ISO1600 might have been another limitation - I was still using the K-01's built-in flash! Maybe I'll get to re-try it this season to see if I can do better. Note that my post just said "decent" results, not stellar.

BTW, I've obtained noticeably sharper results from a 135mm plus reversed 28mm, with more open apertures, lower ISO and a more powerful flash - and a slightly older (and bigger) spider! But that shot could definitely use more DoF! What can I say, field focus stacking is on my list of skills to develop - I've not yet successfully managed a more than two-shot handheld stack of a live subject. I'm not even sure how it's possible, despite seeing many 8+ shot handheld stacks on Flickr...

But I just think it's important (and fun) to experiment, and not be afraid to break a few rules and see what happens. For instance, many people claim it's impossible to shoot greater than lifesize without a tripod. I'm not willing to simply accept that as a given, without even trying it. For diffraction - and discounting focus stacking for a moment - I'd rather get an equally soft shot the harder way (with, say, 6:1 optics) than the easier way (say, 3:1 plus a massive crop). In so doing I am exploring boundaries and (hopefully) honing skills - such as the ability to tell where the camera is pointing at high magnification - that will make me a better shooter when I try a shot with less magnification and/or more appropriate optics. And I'm having fun, which is sustaining my interest in photography. In the end, I'll likely agree with some parts of the photographic "lore" (say, regarding diffraction in high magnification macro) and maybe not others (say, that it's impossible to shoot handheld above 1:1)...

QuoteQuote:
I find that 4:1 is about the useful limit when using SLR lenses, and that only with a particularly good secondary lens set to its optimum aperture. 3:1 is a more practicable limit. When I want to go higher than that I reach for a specialized bellows lens or a microscope objective. And at those magnifications stacking becomes mandatory.
I certainly agree that north of 3:1, things get pretty tough, and your words of wisdom are duly noted. But I'm still hoping to get a better than just decent, field-stacked, 135mm plus reversed 28mm shot of a jumping spider.


Last edited by Doundounba; 02-05-2015 at 08:07 PM.
02-06-2015, 12:54 AM   #8
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I've ordered on ebay 49-49 mm and 49-52 mm coupling ring. They cost almost nothing, let's see if they arrive.


Then I could try both DFA100-FA50(28) and F135-FA50(28) combination.


QuoteOriginally posted by Doundounba Quote
And don't forget to stop down the reversed lens as much as possible.

I'm quite sure I've read somewhere here on the forum a tutorial which said that the reversed lens should be kept wide open. So probably that was wrong.


Is it so that the normally mounted lens should be wide open and the reverse stopped down? So then it would mean that I control the DoF by the aperture ring of reversed lens?
02-06-2015, 01:09 AM   #9
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QuoteOriginally posted by zzeitg Quote
I've ordered on ebay 49-49 mm and 49-52 mm coupling ring. They cost almost nothing, let's see if they arrive.


Then I could try both DFA100-FA50(28) and F135-FA50(28) combination.





I'm quite sure I've read somewhere here on the forum a tutorial which said that the reversed lens should be kept wide open. So probably that was wrong.


Is it so that the normally mounted lens should be wide open and the reverse stopped down? So then it would mean that I control the DoF by the aperture ring of reversed lens?
no, keep the reversed wide open. Or you won't have any light at all. It doesn't make sense to close the reversed lens if you picture it in your mind.
02-06-2015, 01:26 AM   #10
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QuoteOriginally posted by Doundounba Quote
And don't forget to stop down the reversed lens as much as possible.
QuoteOriginally posted by Volker76 Quote
no, keep the reversed wide open.

you guys are confusing me
02-06-2015, 06:08 AM   #11
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QuoteOriginally posted by zzeitg Quote
you guys are confusing me
There is some debate about the issue. When I started using coupled reversed lens technique, I asked for advice about that in this thread, which itself references another thread in which people argued about the same topic. You can see what I was told then, which includes Nass (an extreme macro expert) opining in favor of stopping down the reversed lens. But I've experimented with both since, and I find that stopping down the primary more often leads to vignetting (though it's true that with some secondaries - like a fast 50, usually - you can stop down only the primary without vignetting), plus it seems to me that stopping down the secondary has more of an effect on depth of field (but I've not tested that impression rigorously)...

It's certainly true that stopping down the reversed lens will make shooting much less convenient. You may have to switch to liveview because the viewfinder gets too dark, and even in liveview having enough light to focus can be a problem. Such is life.

But by all mean, don't take anyone's opinion for granted - simply go out, try it, and tells us your own newly formed opinion afterwards!
02-06-2015, 06:36 AM   #12
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Which type of ring to use depends mainly on what lenses you have and how much magnification you need.

The single lens reverse ring (type 2 above) is simpler to use but I''m not sure how to calculate magnification from the focal length of the lens. In a quick test I found a 50mm normal lens was about 0.5x and a 28mm prime was about 2x. You can always add K-mount bellows or extension tubes between the camera and reverse ring too.

The dual lens reverse ring (type 1 above) you divide the focal length of the primary by the focal length of the secondary (reveresed) lens. So if you had a 24mm and 100mm lens combination the magnification would be around 4x.

As far as the controversy as to which lens to stop down on the combination stack I would go with Extreme Macro's recommendation of stopping down the reversed lens. You can always run test and decide for yourself which give better results. If you think about it though if putting the diaphragm closer to the camera gives better results than bellows would have put a diaphragm at the camera end of the bellows which would have made life a lot more simple to give auto stop down function. The primary lens becomes more or less just an expensive extension tube.
02-06-2015, 06:47 AM   #13
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Pascal sums it up well -- much depends on the particular lens combination, and vignetting may decide the issue for you. After all, if you use a Raynox the only control you have over aperture is with the primary lens. There's also debate about where to focus each lens. As a rule, with stacked lenses I focus each lens at infinity, leave the primary wide open, and stop down the secondary. I'm rarely shooting handheld with this magnification, so am not so concerned about the very dim viewfinder image, but for handheld shooting it is certainly worth looking into leaving the secondary wide open and controlling aperture at the primary.

For handheld field stacks, it's helpful if you can prop camera or hands/elbows against something, making small controlled camera movements easier.

Pascal, I applaud you for your experimentation and willingness to do things the hard way. With extreme macro it can pay off to question the conventional wisdom. As you point out, the notion that above 1:1 you need a tripod is silly; just look at Thomas Shahan or Don Komarechka for outstanding counter-examples. One bit of common lore I have found to be bogus is that bare extension is optically better than lens stacking, because there's less glass involved. It's simply not true -- I've done extensive (and tedious) testing and found that many lenses that are mediocre reversed on bare extension are excellent as supplementary lenses, and that my best lenses for reversal are just as good either way, with improved performance in the corners when stacked.

---------- Post added 2015-02-06 at 08:48 AM ----------

QuoteOriginally posted by Not a Number Quote
I''m not sure how to calculate magnification from the focal length of the lens. In a quick test I found a 50mm normal lens was about 0.5x and a 28mm prime was about 2x.
With both lenses at infinity the magnification is simply the ratio of the focal lengths, primary:secondary.
02-12-2015, 03:50 AM   #14
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Ok, the magnification tables for using the Reverse K-Mount 49mm 52mm can be found in the instructions here on Ricoh US
Downloads & Literature - RICOH Imaging

SMC Pentax lens:
28mm f/2 ×2.12
28mm f/2.8 ×1.78
28mm f/3.5 ×1.90
30mm f/2 ×1.83
35mm f/2.8 ×1.18
35mm f/2 ×1.40

These must be based on M series lenses as the 30mm is only in the M series. It is interesting to see how much the magnification varies with the different models of the same focal length. Much of it depends on where the primary plane (optical center) is of the lens.
02-12-2015, 07:09 AM   #15
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QuoteOriginally posted by Not a Number Quote
It is interesting to see how much the magnification varies with the different models of the same focal length. Much of it depends on where the primary plane (optical center) is of the lens.
All makes sense when you compare the size of those three 28mm lenses:
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