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03-08-2014, 04:02 PM   #1
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Macro advice-extension tubes

Wanting a lens for closer focusing, some macro ability would be nice at times. I would appreciate your thoughts and experiences. A friend is also curious about how well the extension tubes work for macro work.

03-08-2014, 04:14 PM   #2
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There are so many options when it comes to macro, what is best for you really depends on what you will be doing. Your subjects will determine the magnification and the working distance (focal length) you need.

Extension tubes are great, I use them with a variety of lenses and they can be combined with a dedicated macro lens for even more magnification.
03-08-2014, 04:37 PM   #3
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The lens you're using is important. A lens without an aperture ring won't work well at all, unless your tubes have electrical contacts. Those tube sets can be really expensive, and no one sells new versions for K mount. The rarest versions maintain autofocus. You can get a full set of the cheapest tubes and several M lenses for less.

Another lens issue is light loss. You want enough light to focus, which you are probably doing manually. As you move the lens further from the sensor, the light spreads out. A lens like the Pentax-M 50mm f4 macro can look like f8 on tubes. Switch to a Pentax-M 50mm f1.7 and it's much easier to see and focus.
03-08-2014, 07:27 PM   #4
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QuoteOriginally posted by wiley old goat Quote
Wanting a lens for closer focusing, some macro ability would be nice at times..
If your wanting macro it's best to find 1:1 here are some examples.

AF New : Tamron SP AF 90mm F2.8 Di Macro, Sigma 70mm F2.8 EX DG Macro, SMC Pentax-D FA 100mm F2.8 Macro,

AF Old; SMC Pentax-FA 100mm F2.8 Macro, SMC Pentax-F 100mm F2.8 Macro, Sigma 105mm F2.8 EX DG Macro

M: SMC Pentax-A 100mm F2.8 Macro, Sigma 90mm F2.8 Macro w/ 1:1 Adapter, Tokina 90mm f2.5 AT-X Macro W/1:1 adapter, Vivitar Series 1 105mm f2.5 Macro, Ricoh Rikenon-P 105mm F2.8 Macro (rare to find)

I'm sure there are others I have not listed. I personally have the Tamron SP AF 90mm F2.8 Di Macro and find it a wonderful versatile.

Another that does close focus to 1:2.9 I own is the Sigma 17-70mm F2.8-4 DC Macro HSM (Contemporary). It basically lives on my camera it such a great lens for the price.

Another way to get close focusing is through using a good set of Close focus filters. The up side is you don't lose any light, can auto focus , Auto Exposure & stack for more magnification. The down side is they can be softer, especially around the edges and may have fringing.
Instead of using extension tubes you could pick up a set of bellows. KEH usually carries them for under $100.00. They are a little easier to focus with then using extension tubes from my experience.


Last edited by Oldbayrunner; 03-09-2014 at 05:59 AM.
03-08-2014, 09:33 PM   #5
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If the budget is tight, the older 1:2 macro lenses can be a real bargain. They are just as sharp as the newer ones, the only drawback is the inability to focus closer that 1:2. I use an M 100/4 macro (1:2) and have a 50mm extension tube with aperture levers (no electrical connections) that changes the focal range from infinity down to 1:2 to the new range of 1:1 to 1:2. They are manual focus (use Catch-In-Focus) and manual exposure (use the green button) but are still as sharp as can be, and they are flat field lenses. The lens focuses edge to edge at the same distance. Most lenses other than macro lenses have a curved field. For bugs it doesn't matter much, but for anything flat, it's a deal breaker.
03-08-2014, 10:43 PM   #6
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There is also lens reversers that you could use. They're very cheap and with a proper lens, they work good. A big advantage is that you won't loose light with them. But you need a manual aperture control on the lens. And you lose autofocus ... but in macro work, it shouldn't be an issue.

I use a Vivitar 2x Macro teleconverter which I love. Paired with a 50mm f/1.7 I end up with a 100mm ~f/4 which still gives me a ton of light and optically it isn't so bad. And unlike other options, with a few twist of the wrist my lens is usable normally and allows infinity focus. No AF but full aperture control. I tried tubes but swapping them got old very quick. I then tried a reverser which was not bad at all but it was very cheap (ebay) and it was leaking light through the mount badly and the lens side thread never provided a safe feeling fit (if you go with a reverser, pay more than $10) Also, only my lens with 49mm filters would fit. So I stuck with the tried and true 20yo Vivitar.
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