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03-29-2011, 05:36 AM   #31
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macro working distance for reversed lenses...

QuoteOriginally posted by Egg Salad Quote
newarts:............
Which is why I would rule out everything smaller than MF - if I invest in a lens I don't really need it should offer another use, too.
Although $30 for the Adaptall is near to nothing..................
I doubt you'll do a lot of work above 2.5:1 as it is difficult but I'll include 5:1 in the following table of estimated working distance vs reversed lens type on tubes or bellows to show how working distance changes with magnification. Working distance for a reversed camera lens is close to focal.length/magnification + registry.distance.

Lens type .......2.5:1 mag.......5:1 mag
Kiev88:45mm.....92mm............83mm
Kiev88:65mm....100mm............87mm
Adaptall:28mm...66mm............60mm
Adaptall:50mm...75mm............65mm
PentaxK:28mm...56mm............50mm
PentaxK:50mm...65mm............55mm

I hope experienced macro photographers will comment on the value of a few mm working distance at these magnifications. It seems to me that squeezing lighting into a 50mm space is a lot more difficult than squeezing lights into a 65mm space but maybe not if you get the right kind of lighting (like fiber optics perhaps.)

03-29-2011, 05:45 AM   #32
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see the shot below, a bellows has to be the cheapest way to get really good macro.

Excluding the enlarging lens, this set up as shown cost $40



as shown this has a 135mm F4.5 enlarging lens which is a flat field lens. The bellows can accept T mount rings in the front, as can the Miranda extension tubes.

To convert the miranda rear mount (bayonet) to pentax, I cut the miranda byonet off the rear lens mount and epoxied an M42-K flanged adaptor.

I can replace the enlarging lens with an M42 thread mount since the enlarging lens is epoxied into a T mount adaptor ring. Then I can put any M42 lens onto this.

you can start with something as cheap as a 55F2 super tak or SMC tak which may only cost $15-30, and get good macros with the most coveted feature of all, working distance.

In terms of bellows units, I like ones like this which have a moveable tripod mount. This allows for rough adjustment of camera position when you preset your focus for an enlargement ratio, If you lack this feature you are into getting a macro focusing rail, or moving the tripod to make this adjustment

Last edited by Lowell Goudge; 03-29-2011 at 05:51 AM.
03-29-2011, 08:04 AM   #33
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QuoteOriginally posted by GibbyTheMole Quote
Abbazz:

I'm intrigued... So, is it just a matter of mounting those lenses onto a bellows? Then focusing by adjusting the bellows in or out?
Yep... You'll only need to find a way to mount the lens -- the easiest way is to cut a hole of suitable diameter in a black plastic body cap and to glue the lens in place.

I have never used these particular Ilex lenses, so I can not absolutely guarantee that they will work right out of the box but, at this price point, you may want to give it a try. I have a few similar lenses from Surplus Shed, and they have proven that they are able to deliver excellent results.

The main concern is coverage, because these lenses may have been designed to cover a smaller format than your Pentax sensor. But lenses have much better coverage at high levels of magnification than at infinity, so this shouldn't be a problem, except if the lens tube or some internal baffle gets in the way, causing vignetting, in which case you will have to resort to lens surgery (Dremel).

Usually, these lenses have a fixed aperture (usually something like F/4.5 or F/6), but anyway you would not want to close the aperture any further at 5x magnification, because of diffraction. Of course depth of field will be razor thin at this level of magnification, but focus stacking is the answer, not closing down the aperture.

Cheers!

Abbazz
03-29-2011, 04:19 PM   #34
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Abbazz & Lowell Goudge:

Thanks for the great info, guys... I'm totally going to get the cheapie industrial lenses, body caps & bellows & have some serious fun!

And if the cheap lenses don't do the trick, I'll pick up some cheap M42 thing from eBay & see what I can do.

Cheers,
Bob :-)

03-30-2011, 02:14 AM   #35
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@Abazz,
The SurplusShed site is great! Strange selection, great prices, reasonable shipping, and they take PayPal. Another drain for my misbegotten lens-trading profits. Anyway, I just ordered the lenses you suggested, and a couple others, including a weird 160mm lens-mirror-prism assembly (US$15). Five lenses, $24 + $5 shipping, wow! And I'm dreaming of some of their aerial cameras...

QuoteOriginally posted by GibbyTheMole Quote
I'm intrigued... So, is it just a matter of mounting those lenses onto a bellows? Then focusing by adjusting the bellows in or out?
Yes, but... many process / projection / macro / enlarger / copy / raw lenses have strange mounts, if any. My favorite ways to use such lenses:

* A plastic body cap that fits the bellows or tubes. Dremel-out a hole to fit the lens. One-buck adapter!
* Cheap macro tubes. Glue a tube section to the lens body, use the tubes' base as a mount adapter.
* Keep a batch of step rings handy. Just in case.

Some such lenses have aperture rings. Most don't. Macro work with wide-open lenses gives micron-thin DOF. You can maybe increase DOF slightly by making a choke or Waterhouse stop to fit behind the lens -- just a disc with a hole in it. But that likely won't help much.

Some of these high-magnification lens assemblies aren't really built for dSLR geometry, but they're cheap enough for experimentation. You might have to skip the bellows, just put the adapted lens on short tubes or even straight on the camera, to get anything like a usable working distance. And don't be surprised if the projected image circle doesn't fill the sensor frame.

But basically, if a lens has an appropriate focal length and image circle, then yes, you just focus with the bellows, or with a combination of bellows setting and moving forward and backward until you get the focus you want.
03-30-2011, 11:58 AM   #36
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Abbazz,
for a price of $2,25 each, these microscope lenses are no hard decision.
Don't know if I can get something like these around here, too.

I have a ringflash, normal flash and bright lamp so I could come up with something.
What I meant is that getting a professional macro lens and using it with an amateurish lighting would be a waste.

Lowell,
I have no idea how you can find accesories so cheap. The cheapest bellows I could find is more than $65 - without lens.
Unfortunately I don't know any thrift shop to look at.

Flat field focusing is another reason why I want a large format lens.
They may have curvature but on APS-C it won't be visible I guess.

I just bought a focusing rail so I won't need a 2 geared bellows unit but I'd still prefer one.
I have good lenses so that's not the issue, either.
03-31-2011, 02:37 AM   #37
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QuoteOriginally posted by Egg Salad Quote
I have no idea how you can find accesories so cheap. The cheapest bellows I could find is more than $65 - without lens.
Unfortunately I don't know any thrift shop to look at.
I have bought several bellows on eBay, in both M42 and PK mount, all in the range of US$20-$35. In one auction, I won an M42 Bellowscope with a Steinheil Culminar VL 105/4.5 lens and hood, for US$42 together, shipped. I can search eBay Cameras for BELLOWS -DUST -MANUAL -BROCHURE and find this [ Magic Automatic Bellows P. Mount M.A.B. ] and this [ NOVOFLEX FOLDING BELLOWS UNIT SCREW TYPE BOTH ENDS ] and this [ HONEYWELL PENTAX FOLDING BELLOWS UNIT ] and this [ KOPIL FOLDING BELLOWS UNIT ] for example. Hmmm, looks like I have overpaid!
03-31-2011, 05:00 AM   #38
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QuoteOriginally posted by GibbyTheMole Quote
Thanks for the great info
You're welcome, Sir.

QuoteOriginally posted by RioRico Quote
Yes, but... many process / projection / macro / enlarger / copy / raw lenses have strange mounts, if any. My favorite ways to use such lenses:

* A plastic body cap that fits the bellows or tubes. Dremel-out a hole to fit the lens. One-buck adapter!
* Cheap macro tubes. Glue a tube section to the lens body, use the tubes' base as a mount adapter.
* Keep a batch of step rings handy. Just in case.
My favorite contraption for lenses with strange mounts is called an universal iris lens holder. It's like a very sturdy iris diaphragm that can be adjusted to any diameter by turning a button and then locked by turning another button. Here's the beast:



I have mounted this iris lens holder in front of a Russian PZF bellows (bought mine with a 50/2.8 Tessar for $15; nowadays commonly available for $20-30):





This particular model can be used to hold firmly any lens from a few millimeters to 56mm in diameter (here, an old 58/2.4 Takumar lens in 37mm screwmount):



With 300mm bellows extension, this is the ultimate weapon for DIY macro:



Of course, there's a catch... These iris lens holders have never been very common. As they are so useful, many lens collectors have begun to snatch them, making them very rare and pricey items... If you ever meet one in a garage sale or in an old and dusty shop, don't hesitate and buy it on the spot!

Cheers!

Abbazz

03-31-2011, 06:51 AM   #39
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Of the regular camera lenses, what's the best focal length/aperture lens to use for macro bellows shooting?

I have one of these zooms I thought might make a good choice:

SMC Pentax-A 35-105mm F3.5 Reviews - Pentax Lens Reviews & Pentax Lens Database

The reason being it's exceptional optical quality & variable focal length from 35-105mm... Of course, I'd have to get a pk mount bellows.

Cheers,
Bobbo :-)
04-01-2011, 01:27 AM   #40
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Extreme Macro Using Eyepiece Projection

There is, I think (hope) a way to get large magnifications at a comfortable distance:





This technique is based upon EYEPIECE PROJECTION, using an astronomical eypiece - here a cheap Plössl 9mm one - to project and enlarge the image from the prime lens.

Curiously, while there is an abundant litterature about this application in astrophotography, I have yet to find a reference for this application in macro photography. However, I am writing on a small tutorial on the subject that you may find here:

Extreme Macro Using Eyepiece Projection

I am still in the testing and veryfication phase, but I think this technique bears some promises in it.

B.R. / Steen G. Bruun
04-01-2011, 04:42 AM   #41
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Stone G's scheme sounds workable with high quality lenses; magnifications would multiply.

I don't have the necessary equipment with me or I'd try it. Here's how the numbers work out for using camera lenses.

Stack a 50mm lens onto a 28mm lens so the 28mm lens looks at the real image from the 50mm lens which is looking at the subject. Arrange each lens for a magnification of 2x -a total of 4X. Here's one way to do it....

Put a 28mm lens is on the camera with an extension tube to get 2x (56mm of extension tubes). Put a bellows on the 28mm lens then a 50mm lens on the far end of the bellows; adjust the bellows to get a 4x image. The working distance (from the 50mm lens to the subject) will be 75mm.

Here's how the distances work out:

|camera|...56mm tube..|28mm lens|.................194mm bellows......................|50mm lens|

There is a small problem here in that the bellows (between the 28 & 50mm lenses) must be 194mm long; that's a long bellows!

A solution is a longer tube on the 28mm lens so a shorter tube on the 50mm lens can be used.

I'd like to know how it works if someone tries it!
04-02-2011, 11:41 AM   #42
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QuoteOriginally posted by Abbazz Quote
My favorite contraption for lenses with strange mounts is called an universal iris lens holder.
That is a pretty dandy-looking contraption! Rather like the inverse of the Raynox close-up lens universal-mount adapter. Yes, I must find one!

QuoteOriginally posted by Stone G. Quote
This technique is based upon EYEPIECE PROJECTION... I am writing on a small tutorial on the subject that you may find here:

Extreme Macro Using Eyepiece Projection
Very interesting piece! I just dug through my hardware -- I have several bellows, many many macro tubes and mount adapters, but no eyepieces, alas. I *do* have some 2" projector lenses. I tried using those, set inside macro tubes between objectives (variously 55mm and 135mm) on bellows, but what I get are inverted images with no magnification. Guess I need to find a cheap eyepiece.

QuoteOriginally posted by GibbyTheMole Quote
Of the regular camera lenses, what's the best focal length/aperture lens to use for macro bellows shooting?
Sorry, that's like asking "What's the best portrait lens?" It depends on what and how you shoot. Shorter lenses force you to work closer, but allow easier frame-filling and greater magnification. Longer lenses allow (or force) you to work further, but much more extension is needed for greater magnification. If you're shooting flat subjects, you'll want a lens with edge-to-edge flatfield sharpness, not a general-purpose zoom. And if you're doing moody impressionistic shots of rounded subjects, anything goes.

Here are some guidelines for APS-C cameras with bellows:

* 28-35-50mm primes are good for close (studio) work, as are reverse-stacked lenses.
* Use 75-100-135mm+ primes for further (field) distances, and for subjects that will flee if a big lens approaches.
* Macro lenses, or cheap enlarger lenses, are needed for sharp flatfield work.
* Zooms, and cheap wide-open projector lenses, and +diopter strap-ons, are fine for impressionistic shots.

So to select lenses, think about your subjects and your goals. And your budget, if any.
04-02-2011, 12:35 PM   #43
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QuoteOriginally posted by RioRico Quote
.......
Very interesting piece! I just dug through my hardware -- I have several bellows, many many macro tubes and mount adapters, but no eyepieces, alas. I *do* have some 2" projector lenses. I tried using those, set inside macro tubes between objectives (variously 55mm and 135mm) on bellows, but what I get are inverted images with no magnification. Guess I need to find a cheap eyepiece..

You might try camera lenses with stacked bellows.

Camera||Bellows2||Lens2||Bellows1||Lens1------------->

The front lens' image is inside the bellows between it and the shorter second lens. The short second lens looks at the image projected by the front lens. I suggest a 35mm front lens so its image will fall inside Bellows1... its image will be 81mm inside the bellows when it is looking at a subject 70mm in front of it.

To get magnification the short lens on bellows2 can look at the real image from the lens in front as closely as you like. The image in the camera will be inverted. Say the second lens is 24mm - at 4:1 it should be 24+24/4 from the image it is looking at - that makes Bellows1 about 81+30 = 111mm.

I don't think it will be easy to adjust.

If you want the working distance to stay constant, both bellows will need to be adjusted for each magnification. If the working distance can vary then only one bellows need be adjusted....but that's no different from the situation with any macro lens.

It is optically the same as using a projecting eyepiece but it'll assemble easily and the camera lens will be at least as good as the eyepiece.

Here's the math I think
mag = (x1/f1)(x2/f2 - 1) - x2/f2(1+f2/f1) +1 ....where x is extension (including registry for camera bellows) & f is focal length.

Last edited by newarts; 04-02-2011 at 05:08 PM.
04-02-2011, 02:54 PM   #44
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@ newarts and RicoRico,

newarts is right of course that the optical quality is of major importance with Eypiece Projection and that photographic lenses are to be expected to be more trustworthy in that respect.

However, one should bear in mind that short Focal Lengh eyepieces have a number of benefits in respect of size and weight (you don't really need a lot of glass to project a tiny part of the image created by the photographic lens). And most of all, I believe that a short FL will be mandatory in practice - otherwise you get cumbersome long projection distances. (I had "real" flowers and insects in the field in mind, when I "invented" this system).

I think that around 10 mm FL is about right for serious experiments with this technique.

And eyepieces come in many prices and qualities too! I paid around 35 US$ each for my eyepieces (brand "ASTRO" from Taiwan) and you can get a variety of same in the uS for a little less. You can also find short focal eyepieces at prices of several hundred dollars, but they are mostly extreme wide-field, say 80 degress FOV - and THAT comes at a price.

We do not need that for photography and a quality orthoscopic eyepiece (with a FOV around 45 degrees) designed for planetary photograpic work should be a good option, or so I think...

At least that's the path I shall follow, but it would of course be very, very interesting to see alternative results based upon real camera lenses!

B.R. / Steen G. Bruun
04-02-2011, 06:15 PM   #45
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Thanks for the above. I'll see what I can put together.
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