[cbaldeck]

When I was shooting macros with my Nikon cameras, I got spoiled by having a 200mm macro lens, along with a good selection of shorter focal length prime macro lenses. I found that I preferred manual focus for this kind of work, so when I acquired a Pentax K1, I gradually accumulated some of the more “normal” focal length manual focusing macro lenses in K-mount, including the SMC-M-50mm f4, the Vivitar (Komine) 90mm f2.8 (1:1) and 135mm f2.8 (1:2) macros, and a Vivitar 100mm f3.5 (1:2 “plastic fantastic”) and I started looking around for what was available for a 200mm macro in K-mount. I found that the A-mount 200mm f4 (green star) macro was very highly rated, but almost impossible to find, even at collectors prices. But I did find and recently acquired an A-200mm f2.8 (green star) lens, also highly regarded, but which only can focus down to about 8 feet.


So my question is: Is there a practical way to get the A-200mm f2.8 (green star) lens to focus down to around 1:2 without loosing any more image quality than necessary? I do have another way to get to about 200mm with one of my shorter lenses, by adding a Vivitar 2x macro focusing teleconverter in K mount, but this involves the addition of glass elements in the adapter, and I wonder if this combination may not be up the the image quality level of the “green star” series.


One other possibility is using extension tubes with the A-200mm f2.8, or perhaps the Canon 500D achromat close-up lens (which is available in 77mm thread size).


Comments and suggestions are welcome.

[Adam]

Tubes would be the way to go IMO. But you might need quite a few of them to get the magnification you're looking for!

[stevebrot]

The A* 200/2.8 is a very fine lens, but is not a macro. Although there are no current K-mount macro offerings at/near that focal length, there have been in the past:

• Pentax FA* 200/4 Macro
• Pentax A* 200/4 Macro (which you know about)
• Sigma 180/3.5 APO EX DG IF Macro

[stevebrot]

But you might need quite a few of them to get the magnification you're looking for!

Yes! About 100mm worth to get 1:2


Steve

[TwoUptons]

Several folks here have had good luck with the Raynox adapters on the slower f4 non-macros.

I expect the Canon achromat would work about the same, but I’ve not heard of many people using the f2.8 lens as a base...

-Eric

[UncleVanya]

I have used the Canon 500D with my DA* 200. I like the combo. The Cambridge site says I'm around 0.68x with that combo. Your A* should be about 0.6x due to the longer mfd and lower native max magnification. (0.14x for the A vs 0.2x for the DA).


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[monochrome]

Yes! About 100mm worth to get 1:2


Steve

From time to time you can find the 100mm Auto Extension Tube K on auction sites. I once had one but (alas) I sold it on years ago. The Auto Extension Tubes pass the aperture lever position through to the camera aperture detector arm (if present) and at least marginally help with Green Button metering.

[cbaldeck]

From time to time you can find the 100mm Auto Extension Tube K on auction sites. I once had one but (alas) I sold it on years ago. The Auto Extension Tubes pass the aperture lever position through to the camera aperture detector arm (if present) and at least marginally help with Green Button metering.

Thanks for that suggestion. Most of the time I don't need to go all the way to 1:2, and since 100mm is in "bellows territory" that might be more flexible than a fixed tube. But I'd have to be careful with that heavy a lens leveraging on the bellows. Maybe someone's suggestion of the Sigma 180 macro would be more practical.

[monochrome]

Thanks for that suggestion. Most of the time I don't need to go all the way to 1:2, and since 100mm is in "bellows territory" that might be more flexible than a fixed tube. But I'd have to be careful with that heavy a lens leveraging on the bellows. Maybe someone's suggestion of the Sigma 180 macro would be more practical.

That’s a fine lens. FWIW, there is also a 50mm Auto Tube. My longest true Macro is a 105.

.:

[Derek]

This thread got my curiosity going.
My A* 200/2.8 and a set of Pentax Auto Extension Tubes (57mm) show pretty close to 1:2 when focusing on a tape measure, but not quite. That's about a 24" working distance on a full frame body.(LX).
Add a 1.4x-s TC and your getting towards 1:1.5 though much closer to the subject and lots of light loss.
As you mentioned there's a heap of weight out front that would need to be cradled one way or another, but I think I'll try this hand held with flash sometime this summer.

Derek

[UncleVanya]

This thread got my curiosity going.
My A* 200/2.8 and a set of Pentax Auto Extension Tubes (57mm) show pretty close to 1:2 when focusing on a tape measure, but not quite. That's about a 24" working distance on a full frame body.(LX).
Add a 1.4x-s TC and your getting towards 1:1.5 though much closer to the subject and lots of light loss.
As you mentioned there's a heap of weight out front that would need to be cradled one way or another, but I think I'll try this hand held with flash sometime this summer.

Derek

This calculator suggests the minimum distance would be farther, but obviously your seeing closer focus.
Macro Extension Tubes & Close-up Lenses

[beholder3]

Comments and suggestions are welcome.

Take a look at the DA* 300mm. If you combine that with a x1,4 TK you get 1:2,9 from as far as 140cm. Full autofocus.

If you use a 25mm Kenko PzAF Uniplus Tube 25 (this even allows SDM AF) you can get 1:2,3.

[Derek]

This calculator suggests the minimum distance would be farther, but obviously your seeing closer focus.
Macro Extension Tubes & Close-up Lenses

That (very useful) link you provided shows a "working distance" as being measured from the film plane/sensor. I tend to measure working distance
as the distance from subject to the end of the lens, hence the roughly 9" discrepancy.

Yep, there's a whole lotta lens hanging out

Derek

[PPPPPP42]

There are several copies of the lens you wanted on ebay, one of which is under 2k and from a reputable Japanese camera store in excellent condition.

Also for really tiny close macro I use the A35-105 F3.5 (cheap, common and good quality) attached to this which always seems to sell for under $30 but is a huge pain to find, especially the A version.:

It is a 2x teleconverter but the guts come out as a simple finger twist bayonet mount making it a fairly long extension tube which also has A contacts so you can control shutter and aperture with front and rear dials which I consider essential.

When you set the A35-105 into its built in macro setting you then use the lens zoom ring as a "focus" which basically shifts your depth of field closer and farther from a few feet as I recall to actually inside the front lens element (I can focus on stuff touching the glass. You can adjust the actual zoom and the size of the depth of field by physically moving closer and farther away. The focus ring on the lens does basically nothing at that point as the focus range it adjusts becomes almost imperceptibly tiny.

This picture is a dime touching the glass on the lens:

[UncleVanya]

That (very useful) link you provided shows a "working distance" as being measured from the film plane/sensor. I tend to measure working distance
as the distance from subject to the end of the lens, hence the roughly 9" discrepancy.

Yep, there's a whole lotta lens hanging out

Derek

Gotcha. It also showed 0.42x (or there abouts) for that extension so that sounds spot on.