[photoptimist]

Long focal length lenses require long extension tubes to get decent magnification.

30 mm of extension will only "add" 30/300 = 0.1 to the magnification.

If you want a 48 mm x 72 mm (2 in. x 3 in) scene to fill the frame of a K-1 which is a 1:2 or 0.5X magnification ratio, you'll need on the order of 75-80 mm of extension tubes on top of focusing at the minimum focus distance.

If you want a 24 mm x 36 mm scene to fill the frame of a K-1 which is a 1:1 or 1.0X magnification ratio, you'll need on the order of 230 mm of extension tubes on top of focusing at the minimum focus distance.

[WPRESTO]

Consider a Canon 500D achromatic close-up filter (about $125 for 72mm thread). Focus distance would be 0.5 meters with lens set @ infinity. My tests suggest that at f5.6-8 the IQ is essentially indistinguishable from the equivalent close-focus using tubes.

[acoufap]

Approaching K-1's HDR DNG file





K1 - Square mode - HDR setting automatic - DA15 - ISO100 - 1/60s - f/11 - PP near FF square crop - HDR development

I wrote down some post processing notes that address Raw Therapee 5.1, Affinity Photo 5.1 and Capture One Pro 10.1. Interested people can take a look at these notes here.

regards, acoufap

[StephenHampshire]

[Erictator]

Long focal length lenses require long extension tubes to get decent magnification.

30 mm of extension will only "add" 30/300 = 0.1 to the magnification.

If you want a 48 mm x 72 mm (2 in. x 3 in) scene to fill the frame of a K-1 which is a 1:2 or 0.5X magnification ratio, you'll need on the order of 75-80 mm of extension tubes on top of focusing at the minimum focus distance.

If you want a 24 mm x 36 mm scene to fill the frame of a K-1 which is a 1:1 or 1.0X magnification ratio, you'll need on the order of 230 mm of extension tubes on top of focusing at the minimum focus distance.

Ahhh... I figured that there was some undeniable math involved. Thanks for that, it explains everything I needed to know... it's unobtanium as a retail product that would give SDM AF and 230mm of extension.

To be honest, I really don't need fill the frame at 1 to 1 on my K-1... like I said in my post, it's "almost good enough" as-is. Just thinking out loud about the idea and that it would be fun to try if could be done on the cheap.

I do have a stack of auto extension tubes, they pass aperture along, but no AF, not even screw drive, that I could play with... or just slap on my DFA100WR.

Thanks again,
Eric

---------- Post added 06-17-17 at 11:54 AM ----------

Consider a Canon 500D achromatic close-up filter (about $125 for 72mm thread). Focus distance would be 0.5 meters with lens set @ infinity. My tests suggest that at f5.6-8 the IQ is essentially indistinguishable from the equivalent close-focus using tubes.

Now there is an interesting idea... Thanks WPRESTO, I'll keep an eye out for a deal. Is that basically like the Raynox I have seen people talk about? I'm guessing that coming from Canon, it's a step up in IQ.
Eric

[Rupert]

Victoria (shot with FA 77 limited and processed with Silver Efex Pro)

Well done...but it is not easy to beat her in living color......I don't think it is possible!

Not much here ...sap is flowing this morning...how exciting...if you're a a damn squirrel!

"When sap starts to flow, I'm ready to go!"


"This is better than beer on tap!"


Regards!

[WPRESTO]

there is an interesting idea... Thanks WPRESTO, I'll keep an eye out for a deal. Is that basically like the Raynox I have seen people talk about? I'm guessing that coming from Canon, it's a step up in IQ.
Eric

The Raynox seem to have a slightly different design - I suspect there is an air space between the lenses, and I think the Raynox were intended for normal to short tele lenses, although they work very well on 200mm optics. The Canon (and Nikon) close-up filters are traditional cemented achromatics intended for use on longer lenses. The 72mm 500D is a big double lens, therefore a bit heavy, and of course you have to be careful aligning the threads on a filter of that diameter - your hand has a lot of leverage.If I can find a little idle time I'll run some test shots and post them here.

[awscreo]

Rokinon 14mm 2.8, still going through my waterfall pics from Lewey Lake upstate NY

B&W water by Timur Dzhambinov, on Flickr

[fs999]

1. FF Mode • 100 ISO • Pentax DA* 200mm F2.8 ED SDM


2. Crop Mode • 100 ISO • Pentax DA 40mm F2.8 XS


3. Crop Mode • 400 ISO • HD Pentax DA 560mm F5.6 ED AW
Blue Tit


4. FF Mode • 100 ISO • Tokina AT-X AF 28-70mm f:2.8
Fusilli Asparagus with Noilly Prat Sauce

[eaglem]

Sheltering............

[Patriot]

Pentax K-1 smc PENTAX-DA* 300mm F4 ED [IF] SDM ƒ/8.0 300.0 mm 1/400 iso400 (hand held)

Eric is a very sharp photo, I like it.
If you can steadily hold this lens, then I do not see any problems using it for shooting small insects. I was trying to shoot this way, but could not get enough sharp photos.

---------- Post added 06-18-2017 at 02:33 AM ----------

Elephant Rock, Valley of Fire State Park, Nevada
D FA 24-70mm F2.8

[Rupert]

3. Crop Mode • 400 ISO • HD Pentax DA 560mm F5.6 ED AW
Blue Tit

Some lovely bokeh in that one FS!

Fusilli Asparagus with Noilly Prat Sauce

Looks good enough to try!

Young Newbie squirrel doing a "spout check".


Regards!

[Mock]

The Fish-eye Takumar 18mm f/11 doesn't get any love. I'm trying my best to work with it's "peculiar" qualities. If you treat it like a 1963 Fisheye Lensbaby, then you'll have some fun with it.

F/11 is awfully unsharp, but if you place your subject carefully it can really pop.



Since it is a focus free optic, it's very nice for quick street shots. The hyperfocal distance is 26cm. This shot was defished and cropped, shot at f/22 probably.



I think these flowers have have even been a little closer than 26cm, but shooting at f/32 brought them into the focus plane.



Was being kinda lazy and just set the camera for Av mode so I didn't have to meter things manually. Downside is that the shutter speed sticks to 1/100s.



Another dreamy rendition, f/22 IIRC



Is the tree really blurry, or is it just really windy?



Obligatory camera fashion shoot, this K-1 is sporting a svelte optic from the Takumar collection.

[Kerrowdown]

Oot and aboot with “Femme Fatale” (Pentax-A 50mm F2.8 Macro) and found my first full flower of Rosa Mundi, cross posted.

[ranchy]

FA85




Zeiss 28