[Thagomizer]

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Hi all;

Some technical questions. I have a Super Macro Takumar 50mm f4 macro, the 1:2 version. If I add the correct amount of extension to achieve 1:1, will I have the same working distance and field of view as a 50mm macro lens that has native 1:1 capability? To generalise this question, if I use extension on a non-macro lens sufficient to give me 1:1, will the resulting lens+extension combination have the same working distance and field of view as a true macro lens of equivalent focal length? I'm guessing the answer is "Yes" for both, but I'm no optical genius, so I figured I should consult with the macro shooters here.

I'm going to be doing a presentation giving hints and tips on macro photography. I want to talk about increased working distance and reduced angle of view with longer focal length macro lenses. I wanted some example prints showing these effects, but my only 1:1 macro is a Sigma 70mm f2.8. I have the Takumar 50 and an SMC Macro Takumar 100 as well, and I was hoping to simulate the effects in question using lens+ extension, hence my questions.

[Not a Number]

If you fully extend the macro lens to 1:2 you only need 25mm of extension to get 1:1 reproduction. The macro lens has 25mm of extension built-in. You would need a 50mm extension tube if you leave the macro at infinity. Working distances should be about the same.

[Thagomizer]

I'd forgotten about the extension in the lens itself. If I recall correctly, I'd need to add 50mm of extension to the Macro Takumar 100mm when it's at minimum focus.

[grhazelton]

I think that your "intuition" is correct. My Father shot many flower pictures with a 50 mm and extension tubes or bellows on his AsahiFlex. I use a Vivitar 100 mm f 3.5 macro. Each functions by increasing the distance from the lens to the film, the Vivitar by its focusing mount which will take it to 1:2. The Vivitar will go from 1:2 to 1:1 via a dedicated achromatic close-up lens. I think the major difference between, say, a 50 mm "normal" lens and a 50 mm macro is the focusing mount, which enables the macro to extend the separation from the lens to the film. Extension tubes allow the normal lens to extend as far as a macro lens. Now, a "proper" macro lens, I think, is also corrected for flat field at close focus. For example, I have a 120 mm macro for my 645n which is stellar! But I've read that the 150 mm is better for landscapes. I don't have both, so I can't make a comparison.

Now since the major difference between a 50 mm normal lens and a 50 mm macro is the focusing mount - which enables the macro to extend further from the film - I think that working distance and field of view would be identical if the tubes furnish the same extension as the focusing mount on the macro. For my Vivitar I'm uncertain. IIRC a close-up lens functions by "shortening" the focal length of the lens to which it is attached. Since that "shortened" focal length lens is further from the lens mount it focuses closer. I don't know about working distance or field of view of the Vivitar with its achromat, perhaps others can answer these questions.

[Thagomizer]

Thanks, grhazelton! I'll have to play with what I've got. Right now it's all at home and I'm at work.

[tryphon4]

Well there is a point not to ignore: some lenses, when used at macro distances, are not at their official focal length, it is a common trick.
For example, a 70mm macro could be a 50mm at macro distances. Then the working distance will be about 50mm, like with a 50mm.

BTW, when you add some extension rings (or bellows) to a lens, the working distance will, at 1:1 and beyond, reach the real focal lenght (i.e: my 50mm, at 2:1, 3:1 and so on, will have a working distance of 50mm.)

[Not a Number]

I'd forgotten about the extension in the lens itself. If I recall correctly, I'd need to add 50mm of extension to the Macro Takumar 100mm when it's at minimum focus.

Correct. For the 100mm macro you only need a 50mm extension tube. Indeed the 50mm Extension Tube K was more or less made for 100mm macro K. Download the Pentax Bellows Guide eBook which has the closeup tables for these lenses.

The Pentax Bellows eBook - Articles and Tips | PentaxForums.com

The optical schema on these lenses isn't very complicated with 5 elements in 3 group. The rear element travels together with all the other elements.

Die Cast Pro - Super-Multi-Coated MACRO-TAKUMAR 1:4/100mm
Die Cast Pro - Super-Multi-Coated MACRO-TAKUMAR 1:4/50mm (1:2)

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Last edited by Not a Number; 08-29-2017 at 08:00 AM.

[Thagomizer]

Thank you for the additional information, all.

[raguseiillustri]

Hi to all. I am waiting my first Prime Lens-Tamron SP 90mm F2.8. Di Macro 1:1 . It should come these days. I am great fan of macro photography and I would like to try ultra macro. I am t beginner and any advice will help. I was reading about TC and ET. What would be better choice? TC+ET+Lens, ET+TC+LENS, ET+LENS, TC+LENS? Tnx .

[dConvert]

Hi to all. I am waiting my first Prime Lens-Tamron SP 90mm F2.8. Di Macro 1:1 . It should come these days. I am great fan of macro photography and I would like to try ultra macro. I am t beginner and any advice will help. I was reading about TC and ET. What would be better choice? TC+ET+Lens, ET+TC+LENS, ET+LENS, TC+LENS? Tnx .

All these configurations will work & all will give different results.
TC+ET+Lens will give the highest magnification (assuming all extension tubes are the same length)
Extension tubes have more effect for shorter focal lengths so switching TC & ET will reduce the magnification but increase working distance.


I personally find stacking lenses to be an easier approach to ultra macro, with the wider lens reversed front to front with the longer one & the longer one mounted normally on the camera. Magnification is the ratio of focal lengths with both lenses focused to infinity, focusing the non-reversed lens closer will marginally increase magnification. (50mm reversed on 200mm gives 4x ) I always leave the reversed lens wide open & focused at infinity, anything else increases the chances of vignetting - which can be pretty bad with some lens combinations.

Have a look at Coupling lenses for extreme macro for a better written explaination, along with details on most of the other options...

[Thagomizer]

Reversed normal to wide angle (say, 50mm-28mm) on extension tubes or a teleconverter works, too. The reversed lens has to have an aperture ring, as in the reversed position its linkage is no longer communicating with the camera body. The viewfinder can get dark at smaller apertures. Live view with focus peaking is your friend. Check out Thomas Shahan's results with this sort of set-up: Thomas Shahan!

[BrianR]

Hi to all. I am waiting my first Prime Lens-Tamron SP 90mm F2.8. Di Macro 1:1 . It should come these days. I am great fan of macro photography and I would like to try ultra macro. I am t beginner and any advice will help. I was reading about TC and ET. What would be better choice? TC+ET+Lens, ET+TC+LENS, ET+LENS, TC+LENS? Tnx .

Results may vary with your Tamron, but on my DFA100mm, my first step to get more magnification is the Raynox DCR-250 close up filter. This gets up to 2x magnification (I've made a chart) and maintains all the auto features you love except AF (which is sketchy at this high magnification no matter what). The most important to me is having the camera stop down the aperture when I take the shot so I can compose wide open. The quality is pretty great. There are a few examples in my flickr stream (I usually make note of the DCR in the description), like this one (this is 1.8x mag):





I also have a tamron 1.4x TC, which works pretty well. But unless I really need the working distance I prefer the Raynox.

My next step is reversing a A28/2.8 onto my DFA100mm. This gets me to 3x magnification, but is much harder to work with.

I have a bellows, but they work much better with shorter focal length lenses. Since getting the dfa50mm, my dfa100 will probably never touch my bellows again. If I had auto-extension tubes, I might be inclined to use them on my dfa100mm.

[raguseiillustri]

Tnx to all. As I said it is my first prime. And after reading all you wrote to me I think it is better to start with easy steps and after go further and try reversing technique, extensions..... BrianR's sollution seems to be the most approprite. Would this work on Tamron 90mm macro? What about compactibility with other lenses I use like sigma that are not prime? Thanks in advance. Dont laugh to me
Raynox Super Macro M.Snap-On Adapter DCR-250 | eBay

[raguseiillustri]

About teleconvertors, how do I choose them? According to pentax body or to a lense i am going to put on? For examle I was looking this:
Teleconverter-x2-for-Pentax-AF-KAF2-KA-KAF-FA-K-Autofocus-2x-Tele-rear-converter , it is compactible to the body, the seller told also that it would work with tamron macro even including autofocus.

[BrianR]

Tnx to all. As I said it is my first prime. And after reading all you wrote to me I think it is better to start with easy steps and after go further and try reversing technique, extensions..... BrianR's sollution seems to be the most approprite. Would this work on Tamron 90mm macro? What about compactibility with other lenses I use like sigma that are not prime? Thanks in advance. Dont laugh to me
Raynox Super Macro M.Snap-On Adapter DCR-250 | eBay

It will depend on the lens and settings, some combos work great, some not so great. There is a thread devoted to the Raynox adapters, you might be able to find some examples with the zooms you have:

The Raynox Macro club - PentaxForums.com

Edit - here's more about your Tamron and the Raynox https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/253539-tam...ro-raynox.html

There is also a calculator to approximate the magnification you'll get with the various combos:

Using Raynox Adapters For Extreme Macro

I don't have the DCR150 adapter, but it is another option to consider. It is sometimes less expensive to buy the DCR250 and 150 as a kit. Having both will give more flexibility. They come with clip on adapters, but you can also attach them to your lenses with step up/down rings, which can make for a more compact setup.

It sounds like this is your first foray into macro? If so, you might want to get the hang of your incoming tamron on its own. As magnification goes up, everything gets more challenging. Good luck