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Hi all,

Alright, so I've been really enjoying my macro adventures over the last 8 months or so. I started with a 1:2.8 Tamron Adaptall 35-70 zoom which I already had, to which I added an Adaptall 2X teleconverter for 1:1.4. Then I got a Pentax-M 50mm F/4 and some extension tubes to go to 1:1 and a little beyond. Then I started adding some flash by fashioning homebrew flash diffusers. Then, since I was having more and more fun, I got a real macro - a Tamron 90mm F/2.8 macro - and more tubes. That took me to about 2:1. And for a recent vacation, I didn't want to bring the tubes, so I bought a Raynox DCR250, and I love it!

With the Tamron 90mm, the Raynox and tubes, I can reach about 3:1. Just a few days ago I shot at my highest magnification yet (2.6:1) and did my first "snowflake session". I think it turned out rather well, if I may say so myself.

I can't want to try out this combo on some bugs, but in the meantime it's winter, and I've decided to investigate options for higher magnification. The new Extreme Macro site written by a forum member here has been super useful. I've decided that what I want to try next is "Coupled Reverse Lens" technique. I know, some might say "put a reversed 28mm on a bellows instead", but I am intrigued by the two-lens technique and have some old glass that I want to try out with this (and some that is on the way).

Alright, so I have some questions that I hope people who've actually experimented with this technique can help me with.

1) Is the speed of the reversed lens important? I'm worried about having a bright display - K-01 so liveview it is - with which to focus. My primary will be F/3.5 (a Pentax-M in either 135mm or 150mm). I've got a variety of glass that I want to try reversed. I'm thinking that a faster reversed lens means a brighter image to focus with. Is that accurate?

2) Which lens do you stop down to shoot? If you look at this thread, they talk about vignetting, and then someone comes in and says "you're stopping the wrong lens down!" and proceeds to advise that the reversed lens is the one that should be stopped down. (The coupled reversed lens section of the Extreme Macro site basically says the same thing.) But then on the very next page someone else comes in with a very authoritative voice and says "No! Stop down the primary lens and leave the reversed less wide-open!" And many tutorials on this technique do just that, using tape to hold the aperture open on older lenses. Has anyone tried both options? If so, which do you prefer? I know there is the issue of how to stop down the reversed lens without having pre-set it before approaching a critter and then having to focus with the reversed lens at F/11 or beyond, which is likely the definition of hopeless. But if we just talk about the optical properties, which solution produces the best images?

I'd try it instead of asking, but my primaries and reverse couplers are still in the mail, so I'm reduced to bugging the experts...

Opinions?

1) It's not important, and not necessarily. You're just using it as a converging lens so keep it wide open, but in terms of light transmission, yes you'll get more light but not all f stops are equal anyway, so it's like comparing apples and oranges. Google the difference between f stop and t stop to see what I mean - f stop is just an equation whereas t stop actually measures light.
2) stop down the reverse one. Yes you can stop down the base but it tends to lead to abberations because it's away from the optical centre of the lens. Stopping down the base is like a "mini" f stop change, yes it has an effect but it's not as clean, strong or effective as using the front reversed one. Neither way necessarily avoids vignetting anyway, vignetting is a bit hit and miss to do with the pupil sizes, mag, lens construction type etc. Fwiw, you actually need a higher level of magnification on coupled lenses like this rather than lower. Ie say at 4:1 both wide open, a 50 on a 200 I'd be surprised if you had vignetting but I've had all sorts of vignetting reversing a 50 onto a 50. Why don't you try both and put up some shots

Hello

Great flake shots, I live in Finland and never shotted any flakes!

I have tried some stack and reversed lens combos and all are about 4x or little more:

28mm cosina reversed + 68mm extension:




135mm stacked with 50mm and 68mm extension:




135+45 and 68mm extension:




This is not the easiest way to make high mag shots


LeGu

What was your physical setup for the snowflakes? Where did you shoot, lighting, anything else that might help someone for a first try?

Nass: Thanks for your response - and all your work on the Extreme Macro site! Much appreciated and a very valuable source of knowledge! Certainly, as soon as I have all the parts, I will experiment and report back my own findings. My hope is to reverse a small zoom (28-70) on the 135mm for another version of the poor man's MP-E, with roughly a 2:1 to 5:1 range. But if that doesn't work, my fall back is to carry {28, 50, 135, 150} and decide on the combo "in the field". I just received the macro couplers today, but I'm still waiting on the 135 and 150.

LeGuillotine: Great shots! But you didn't tell us which lens you stopped down!

audiobomber: I wouldn't want to hijack my own thread... But what I found works for me, to shoot "in-situ" - ie just shooting snow as it's naturally accumulating - is a place where the snow is accumulating on some kind of narrow-ish strip. In my case, that's the back external metal stairwell. It's made of black-painted metal "strips" - one stair is maybe 5 metal strips with gaps in between. On those, you can shoot the edge of the accumulating snow without having only more snow as a background (which kills contrast). That really helps, in my very limited experience. Other than that, I just used the onboard flash with my homemade diffuser - two Pringles cans arranged in a telescoping setup. I can take pics if you want. Oh, and because it was evening, I borrowed a floor light from the living room so I could focus. But I didn't need that today as it snowed again in daylight. Oh, and because it's a stairwell, there are many surfaces on which to lean to get more stability, which is really useful at 2.6:1! Finally, try not to breathe on the flakes...

I stopped down those reversed short primes and long ones were wide open.

LeGu

Btw I use two 49mm filters without glas and taped together for connecting short and long primes. Do You know is there some "the best" distance between front lenses?

Thanks for explaining your setup Doundounba. I will have to give it a try. It seems a lot more manageable than the single flake shots.

Generally, the closer the reversed lenses the better, but there's no substitute for experimenting with what you have. With the diversity of lens designs, what works best with a particular pair of lenses is not entirely predictable. AND, reversing rings are relatively cheap. Try www.AdpaterRings.com.

WPRESTO

Hi all,

So the Pentax-M 135 and 150 arrived today - I'm stoked! Merry xmas to me!

Christmas time will make it hard for me to perform a lot of tests, but I'd already started experimenting a little with my Tamron 90mm F/2.8 Macro (272E) as the primary. Here's what I've seen so far:

- Tamron 90 + Tamron Adaptall 28mm F/2.5: Pretty bad vignetting no matter which lens was stopped down, though worse (read crazy bad) if the 90 was stopped down.
- Tamron 90 + Pentax-A 50mm F/1.7: Good results with either lenses stopped down, but not a lot of magnification.
- Tamron 90 + Vivitar 28mm F/2.8: Decent results with the 28 stopped down, awful vignetting with the 90 stopped down. Annoying that the 28mm only stops down to F/16.
- Pentax-M 150mm + Konica Hexanon 50mm F/1.8: Beautiful results with either lens stopped down!
- Pentax-M 135mm + Vivitar 28mm F/2.8: Very good results with the 28 stopped down, moderate vignetting with the 135 stopped down.

Here is a 90mm + 28mm reversed shot of some snow and ice pellets mix that was falling on Montreal on Saturday:




And here is a Canadian Penny macro using the M150 with the reversed Konica 50mm.




And the same with the 135/28 combo, a bit more straight-on:

Alright, I have some more results!

I've also tried to reverse my Sigma Superwide II 24mm F/2.8 on the M 135 and 150, and again, it was better if I stopped down the reversed lens. However at F/22 on the reversed lens, the viewscreen gets real dark and focusing becomes very difficult. But after some more experimentation with various combos, I found that with many combinations, I could open up the reversed lens to about F/11 and stop down the primary to about F/8, and get similar results as if I'd only stopped down the reversed lens, but with a much brighter viewscreen!

So... I researched options for a reversed zoom. And after some trials and tribulations, a Tamron Adaptall 28-70mm F/3.5-4.5 (159A) arrived in the mail today. The combination of this plus the Pentax-M 135mm F/3.5 weighs about 550g - less than a Pentax FA 100mm F/2.8 Macro, for example. Tonight, I coupled the two lenses, set the primary to F/8, the zoom to F/11, and took some test shots.

Zoom at 70mm:




Zoom at 50mm:




Zoom at 35mm:




Zoom at 28mm:




Pretty good results, if I may say so myself! Macro range is 1.9:1 to 4.8:1. Not quite an MP-E, but a reasonable Poor Man's Version, I think. Can't wait to try this on critters outside...

What can I say. Nice!!!

What can I say... Thanks!

I tried some snowflake shooting with my "Poor Man's MP-E" yesterday, and, well... I still have some work to do. I found that it's hard to move the zoom setting on the Tamron when it's not attached to a camera and while also wearing gloves. And it's easy, in so doing, to inadvertently mess with the zoom's aperture and focus settings. I also think I will need to shoot more closed down than F/11 & F/8, for more DoF. It might be sufficient for pennies, but not for snowflakes unless you are totally straight on. It's also pretty hard to light these things properly and small differences in the angle of the flash make big differences in the resulting shot.

I hope we get better flakes soon. It was only -6C and the snow was falling in big wet clumps - not the best conditions. Many flakes had "accreted" droplets of water on their back, which make them thick, but also made for very busy, confusing shots. All in all, I didn't get great results, but live and learn, right?

Here's one of the better shots I did get:

Very impressive work!

Thanks Mark!

After some more use, I am finding the 28-70mm reversed zoom a little suboptimal. The filter ring turns when focusing, so it's pretty much impossible to tape the focus to infinity and the zoom ring (at least on my copy) is very difficult to turn without also changing the aperture setting or the focus. That makes usage not always super fun. Thinking about replacement option, I will certainly try a lens whose filter ring doesn't turn when focusing the lens.

The shots themselves I still like though. Here's another 135mm + reversed 28-70mm snowflake shot:

Great stuff, and you are getting some great DoF, tough for macro! Getting down to f16 or 22 might be good, but you start risking diffraction them which can also give less sharp images.

Burning a candle at both ends!