Macro photos using old zoom objectives (1 Viewer)

Sticking an old zoom objective lens cell in front of a lens will increase its close focus ability by a good margin. Here's one taken buy placing a Tamron 85-210mm BBAR MC lens in front of my Pentax SMC 50mm f1.7 lens.

The old Tamron lens cell is a nice 3 element apo design so it's well corrected.

Paul.

Pin sharp--very impressive.

Thats damn good. I still have the objective ( just the single front lens element we're talking about, isnt it ? ) from the 100-200 Prinzflex that i nicked the TN from.

Might be worth a shot.

I no longer have a macro lens, so i shot this Lacewing with a regular old MF Tokina W/A 28mm, but mounted it on an ext tube.
Its ¾" long, but the eyes are only between 1 and 2 mm across.

The IQ isnt all that much, but it was hand held and difficult because i had to get less than around 10mm from the insect to get a shot.

The 1st shot will increase if clicked twice

Paul, that fly shot un cropped? That would easily be 2:1 magnification.

Mounted my Cosina 70-210 Objective infront of my 18-55 kitlens @55mm, gives me about 1:1 magnification and I can still use AF. Here's one with 1:1 mag MF on a tiny Caterpillar about 15mm long.

Sticking it infront of my 75-300 zoom, the magnification can goes up to something like 5:1 but it's sort of wash out. Tried controlled lighting, dimming etc, still the same. Guess it's gone beyond their useful magnification.

The fly photo was cropped about 50% just to show off the fly. I found different lenses allow for different focusing distances. Some let you get really close, maybe 30mm closer than your Cosina lens of which I have the Vivitar version.

Paul.

My Cosina mounted in front of my kitlens brings me down to 40mm from objective to subject and that gives me about 1:1.

Sorry, it is not a fly.

Tamron 40A (35-135mm) objective screwed-in backwards to front filter threads
Pentax 6X7 165mm lens + adapter, set at f/22
Pentax K100D Super DSLR, ISO 200, +/- 1 stop HDR image (0.7, 1, 3 secs.)
#1 screwdriver ~3mm diameter, ~13mm of length shown, uncropped

Was about 3 inches from the subject, I think about 1.35:1 mag. Not bad for a lens that its normal close-focus ability is 1.6 meters! Typical color, contrast, and sharpening in PSP and Focus Magic. Now, imagine a gigantic bird eyeball staring back at you.......

:t:

goldenarrow said:

Tamron 40A (35-135mm) objective screwed-in backwards to front filter threads
Pentax 6X7 165mm lens + adapter, set at f/22
Pentax K100D Super DSLR, ISO 200, +/- 1 stop HDR image (0.7, 1, 3 secs.)
#1 screwdriver ~3mm diameter, ~13mm of length shown, uncropped

Was about 3 inches from the subject, I think about 1.35:1 mag. Not bad for a lens that its normal close-focus ability is 1.6 meters! Typical color, contrast, and sharpening in PSP and Focus Magic. Now, imagine a gigantic bird eyeball staring back at you.......

:t:

Click to expand...

Trying to picture how you mounted the lens. Was it facing forwards, as it would have been on the original lens or was it reversed? Ideally it needs to face forwards as you get a flat image. Reversing the lens will give distortion in the four corners although the middle will be ok.

Your image looks good though. My lens allows my 50mm prime lens to go down to about 3" where as normally it's around 18".

Paul.

mounting

Paul Corfield said:

Trying to picture how you mounted the lens. Was it facing forwards, as it would have been on the original lens or was it reversed? Ideally it needs to face forwards as you get a flat image. Reversing the lens will give distortion in the four corners although the middle will be ok.

Your image looks good though. My lens allows my 50mm prime lens to go down to about 3" where as normally it's around 18".

Paul.

Click to expand...

Paul,
I had to mount it temporarily reversed, the 58mm threads fitting into a 67-58 step down ring I had for use with my lenses. The rear of the objective housing has some weird ~50mm threads that does not fit my 49mm rings. I have not dislodged the objective housing from the glass since it seems to be a useful holder at the moment.

Thanks for the tip about distortion! I will try to test for that with some graph paper and post it here tomorrow night.

Funny, it seems 3 inches is the distance I get when setting the lens on infinity, the same distance you had. I love the magnification and how clear it came out without having to buy a special close-up lens. I'll try it on my Tamron 28-75mm zoom which also has 67mm threads and see if the distance is different. It is also an autofocus lens, and although the theory is that autofocus usually does not work with macro work, it would be a hoot if this gives me autofocus consistently. I also have a Pentax 1.7x AF Adapter, which is an "autofocus teleconverter", to try on the old 6x7 lens. Cool stuff if it will work with the objective lens mounted!
GA