[FrancisK7]

I'm trying to photograph a seed that is about 2.5mm long. My DFA 100mm macro lens doesn't get me close enough and I'm not satisfied even with a 100% crop.

Can I use extension tubes? I'm not too familiar with macro photography hardware/

[ChrisTrevino]

Yes you can use extension tubes, cheap ones won't let you AF though.

You could also flip the lens around and hold it up to the end of the camera and shoot through it reversed. Focus is a guessing game that way though as the viewfinder is pretty useless when you have to manually stop the lens down to like f/11-f/16 for a macro.

[Bob from Aus]

I almost never auto focus with macro, but then I am usually using flash. keep your subject still prefocus and move your own body/camera to get focused.

Going beyond 1:1 is always difficult and I have about 5 setups that I am unhappy with. I find the best result is with a good times 2 converter. I can't get the quality with any of my other setups.

As you have an aperture ring on your 100mm you can use a reversing ring. I don't have that option with my macros.

[Na Horuk]

You can use lens add-ons (apparently some are actually good, but cheap ones will ruin IQ. I hear good tings about Raynox? Something like that), you can attach a flipped lens (there are reversal rings for this), you can use extension tubes, you can use bellows (allow more flexibility than extension tubes).
But I cant imagine a 1:1 macro lens isnt good enough? I mean, plenty of lenses these days are marked as "macro" but they only go to 1:4 or 1:2. (even primes, not only zooms). Are you sure you are doing it right? For closest macro photography you need to set to MF and spin the focus to closest possible (as in, the other way from infinity) and then move your lens closer and closer until what you want is in focus. Can you maybe post "your best but not good enough" photo of this seed?
You might also want to consider just getting a microscope attachment or an enlarger lens (third-party), if this is not enough.

[Bob from Aus]

You might also want to consider just getting a microscope attachment or an enlarger lens (third-party), if this is not enough.

What is meant by a microscope attachment? It could be interesting.

I have an old pentax microscope adapter (prized possession) but it has crap results on my reasonably good microsope. Unfortunately it is too large to fit onto my better stereo microscope.

[Na Horuk]

What is meant by a microscope attachment? It could be interesting. I have an old pentax microscope adapter

That is what I meant, sorry. I meant an adapter to attach the camera to a microscope. I never actually tried this myself, so I dont know much about the results

[Not a Number]

See this thread
https://www.pentaxforums.com/forums/pentax-lens-articles/152336-cheap-macro-b...lose-work.html

Probably the simplest option is to stack two lenses with a reverse coupling ring. These allow you to couple two lenses together via the filter rings. Magnification is the ratio of the two focal lens. Putting a 25mm lens reversed on your 100mm macro would give you a ~4x magnification. Drawbacks are rear elements of the reversed lenses are exposed, vignetting, edge distortion, might have to find a way to keep the reversed lens wide open. On the plus side you can use any prime lens as the reversed lens (manual focus is ideal) - Minolta, Nikon, Konica etc.

[Bob from Aus]

I never actually tried this myself, so I dont know much about the results

I had been after a pentax microscope adapter for years and eventually picked one up for a song. Was I pleased. I use a K mount adptor for the thread. However I don't get really good results. I suspect I need to kill stain and slice my subjects to do much better. I also have an old 100mm macros and bellows from my Spotmatic days. That combination is also disappointing. Putting my SMC 50 F3.5 on the bellows is like looking down a dark well.

So you can see from this thread I am also interested in what others have to say.

[lightbulb]

This is what we need in K Mount, perhaps. Canon super macro lens MP-E 65mm 1-5x

[Not a Number]

There are T-thread adapters available so that you can mount a RMS microscope objective on to any T2 mount and thus to bellows or extension tubes. Bellows are you best bet with setup. A couple of the bellows lenses Olympus used to make used the RMS thread so if you have their bellows system you can find the adapter plate for the lenses.

Using the microscope adapter presumes you have a microscope to attach it to.

This club thread will give you all sorts of ideas

https://www.pentaxforums.com/forums/lens-clubs/143202-macro-any-means-necessary-club.html

[Stone G.]

I believe that we are many that have found photography through an ordinary microscope a frustrating experience. Contrast is very low while dust and other impurities, such as tiny bubbles in the glass, are greatly enhanced due to the very small f-ratio. But with a seed some 2.5mm long, I would suggest a combo something like this: macrolens + extension tube + teleconverter (in the said order of appearance):



Does it work? Well, take a look at this corn (maize) sample from a children's microscope set:



Here is a downscaled 100% crop taken with the rig shown above (with apologies for the untidy object glass):



And here's a non-resized 100% crop:



My lens is an old Tamron SP Adaptall-2 (Model 01A) lens providing in itself just a magnification ratio of 1:2.5. So, with the OP's 1:1 macro lens I would belive that even more convincing results might be achievable.

[marcusyoung]

This is what we need in K Mount, perhaps. Canon super macro lens MP-E 65mm 1-5x

Yes, canon MPE 65 gives max five times magnification. HOw much magnification does TS need to magnify the image?

For extension tube, an additional 100 mm of tube together with the pentax 100 macro lens will give you 2 X magnification. Add in a raynox 250 and you have much more magnification but you will need an additional source of light externally.

Another option is to use reverse ring method, reverse ring with 28 mm lens will gives about 2.5 X magnification.

Hope this helps

marcus

[audiobomber]

This post shows a D FA 100 macro at 1:1 and magnification with a Raynox 250 added (no cropping).

https://www.pentaxforums.com/forums/lens-clubs/74221-raynox-macro-club.html#post753591

IME, a Raynox will give you quality equivalent to reversing a lens on the end of the 100mm macro, and better than a TC. TC's cause more aberrations (fringing, loss of sharpness).

Adding more glass, whether it's a Raynox, TC or reversed lens onto the end of a main lens gives slightly lower quality than using a single short lens with reversing ring, or extension tubes.

[Bob from Aus]

Does it work? Well, take a look at this corn (maize) sample from a children's microscope set:

I note your small back lighting lighting apparatus. What is it and is it? Is it something you have made?

[marcusyoung]

This post shows a D FA 100 macro at 1:1 and magnification with a Raynox 250 added (no cropping).



IME, a Raynox will give you quality equivalent to reversing a lens on the end of the 100mm macro, and better than a TC. TC's cause more aberrations (fringing, loss of sharpness).

Adding more glass, whether it's a Raynox, TC or reversed lens onto the end of a main lens gives slightly lower quality than using a single short lens with reversing ring, or extension tubes.

totally agree with you..I do own a vivitar macro converter and Panagor macro converter but rarely do I use em. Extension tube is still my preferred choice for higher magnification. Higher magnification also means that any flaws of the lens is more visible thru d image produce. Any part that is not as sharp will be magnifiied too.

marcus