This is a really backdated post.
I got myself a Cosina 70-210mm F2.8-4.0 Macro for Minolta/Sony A-mount for use on my Sony Alpha 100. This is also known as the famous Vivitar Series 1 70-210mm F2.8-4.0 Macro.
This has the same range as the Minolta 70-210mm F4.0 beercan lens I have, but it’s brighter at 70mm.
Cosina 70-210mm F2.8-4.0 apertures:
70mm onwards F2.8
85mm onwards F3.2
120mm onwards F3.5
150mm onwards F4.0
In comparison, the Cosina’s plus points are:
– brighter before 150mm
– has a focus limiter switch which is better than standard focus limiters
– focuses to 1:2.5x macro
– shorter and will fit in my bag with camera body attached
– can be used with my fussy Tamron 1.4x 4-element 5-pin teleconverter
210mm F4 with the Cosina.
The Cosina’s minus points:
– brightline bokeh is obvious
– chromatic aberration is easy to get, so you’d need to stop down to F5.6 for acceptable levels
– it’s a push-pull (no one-handed pinky finger zooming for me!)
– teleconverters exaggerate the spherical aberration and chromatic aberration
I won’t sell the beercan, because of its plus points:
– much better creamy bokeh
– sharp wide open, and superb at F5.6 and darker apertures
– teleconverters show that my beercan has very little spherical aberration or chromatic aberration so the image quality barely suffers
Cosina with the Tamron 1.4x to make 300mm F5.6.
Stopped down to F8 at 300mm.
So what’s special about the focus limiter switch on the Cosina?
It can lock the focus ring from:
– infinity to 2 meters (at this point focus is superbly fast because the gear ratio is different than in macro mode)
– 2 meters to 1.1 meters (when not at 210mm focal length)
– 2 meters to 0.84 meters (at 210mm focal length)
– infinity to 0.84 meters (no lock)
The locked range depends on where you lock it. It just prevents the ring from passing the 2 meter mark.
This is much better than a standard focus limiter on those big lenses, which let you choose either infinity to macro, or infinity to 2 meters.
This makes my encounters with Vivitar Series 1 lenses to total 3; I had the Cosina 19-35mm F3.5-4.5 for Pentax-AF K-mount (sold to Yee Wei), Vivitar Series 1 28-105mm F2.8-3.8 for Minolta/Sony A-mount, and of course this Cosina 70-210mm F2.8-4.0 for Minolta/Sony A-mount.
My run-ins with Vivitar also include the Vivitar 24mm F2.0 for Olympus Zuiko OM-mount, Vivitar 28-70mm F3.9-4.8 for Minolta MD-mount, and Vivitar 75-205mm F3.5-4.5 for Pentax K-mount with 2x matched teleconverter. I’ve never shot through the fungused 28-70mm, but I’ve touched a Vivitar 100mm F3.5 Macro and it was good.
I also got myself a Kenko Teleplus 4-element 8-pin 2x teleconverter for Minolta/Sony A-mount. This converter oddly changes my Minolta 50mm F1.4 into a 105mm F3.5 (though metering indicates a accurate 2-stop loss). Astoundingly, this works with all my lenses unlike my fussy Tamron 4-element 5-pin 1.4x teleconverter. Despite the warning that a teleconverter and lens will only work if the combined total is brighter or equal to F6.3 (e.g. F3.5 lens on a 2x teleconverter cannot be used), the 2x throws that rule out the window. I can use my Sony 18-70mm F3.5-5.6 lens (easily my darkest lens) at 140mm F11.
It is then that I learnt to appreciate the kit lens; it’s astounding even with the 2x teleconverter. Teleconverters expose the weakness of a lens and exaggerate it. The kit lens had little to no loss in quality… while the Minolta 50mm F1.4 just went super soft.
So what if I stacked my teleconverters together?
In order: Sony A100, Kenko Teleplus 2x MC4 teleconverter, Tamron 1.4x MC4 teleconverter, Cosina 70-210mm F2.8-4.0 lens. Accessories include generic right-angle finder and Sony HVL-F56AM flash. (I cannot stack the teleconverters in reverse due to a metal stub on the Tamron.)
You read that right – a 600mm F11!
A CCD-shift stabilized 600mm F11!
For under RM1000!
It lets me shoot at 1/60th of a second! It’s light as heck and fits in my tiny Lowepro Nova Mini AW camera bag. The beercan does, too, but a bit tightly.
So what about in-lens stabilization? Sorry, only certain Nikkor VR lenses can work with teleconverters (or, certain teleconverters work with Nikkor VR lenses). Haven’t read up on Canon’s though.
My Tamron 1.4x teleconverter is fussy, so while the beercan can also give 600mm F11 with better quality, it won’t be as practical.
Shot through a window in afternoon light. 600mm F16 1/60s ISO400.
The Sony A100 can only autofocus at F8 or brighter; at F11, this Cosina combo (which I will call the 600mm F11) is too full of spherical aberration when near focus, the camera cannot possibly focus.
Strangely, though, it is easier to manual focus. The lens feels great for manual focus, and when a black, backlit subject is out of focus, chromatic aberration leaks onto the black and turns it either purple or green. When the object is in focus, it is a solid black!
Alternatively, I could zoom out to 200mm F8 and auto-focus, then zoom in.
The 18-70mm F3.5-5.6 with 2x teleconverter at 140mm F11 is very easy to manual focus too; the entire image melts into spherical aberration softness, and it is very obvious when it is in focus. It feels like the outside matte surface of a split-prism viewfinder on ye olde Manual Focus SLRs. (Of which I have too many of.)
I later found a Tamron 2x 7-element 8-pin Minolta/Sony A-mount teleconverter, but I had already bought the Kenko! Ah heck, I tried it anyway for a 6x effect.
1200mm F22 1/80s ISO100. The camera reported an EXIF of 9999mm while my computer reported an EXIF of 65535mm. Apparently, it couldn’t count to 1200mm, heh. (Nearly focused) out-of-focus is pretty, and obvious.
1200mm F90 1/80s ISO400, still pretty stable. F90 is an errorneous number and it has the same focal length as the previous picture. I can’t remember if the CCD-shift was compensating like crazy.
My Minolta Dynax 7, Tamron 2x 7-element teleconverter, Kenko Teleplus 2x 4-element teleconverter, Tamron 1.4x 4-element teleconverter, Tamron 100mm F3.5 Macro lens. This famous lens allows close focus to 1:2 magnification, and 1:1 magnification with the supplied screw-on lens. This combo gives 3:1 magnification!
65535mm (actually, 100mm 2x 2x 1.4x 600mm) F51 1/125s ISO100. This is a speaker grille at Keat Camera.
Frankly, I found little difference in image quality between the 7-element Tamron and my 4-element Kenko. Results may vary.
So how far can the Sony A100 count?
1000mm F16 1/15 ISO1600. This was with the Sony 500mm F8 reflex mirror lens. It can still (try to) auto-focus! At such slow speeds it cannot be ascertained if it was handshake or motion blur.
500mm F8 1/13 ISO400. Look ma, no donuts! It is up to the photographer, once acquainted with a reflex mirror lens, to hide or emphasize donut-shaped bokeh.
Stopping down my 600mm F11 provided better results. It goes down to F64! At this point any dust on the sensor becomes small and manageable. This is also where I wish for an Olympus Super-Sonic Wave Filter anti-dust solution, because that’s the only one that really works. Shot at 600mm F64 1/160s ISO1600.
600mm F64 1/40s ISO400.
My pride. 600mm F11 1/2s ISO400. Half a second handheld! Handshake and softness is of course apparent, but the size of the subject makes it less relevant.
600mm F11 1/30s ISO1600. When I shot this I didn’t know that light in the sky was Venus. Or was it Saturn?
280mm F7.1; possibly the Cosina at 140mm with the 2x. Its brightline bokeh is very obvious here.
600mm F16 1/80s ISO400, for the birds. Any shorter focal length would need you to step closer… and the birds would fly away. This makes shooting in a bird park a lot easier because them birds don’t fly away.
600mm makes for espionage!
I spy smashpOp!
I spy my boss!
I spy on the police!
I spy the Fujifilm building!
Big macro zooms, left to right: Minolta Dynax 7 with Kenko 2x, Tamron 1.4x and Cosina 70-210mm F2.8-4.0 Macro; Pentax P30t with Vivitar 2x matched teleconverter with Vivitar 75-205mm F3.5-4.5; Olympus OM-2000 with Vivitar 2x teleconverter with Soligor 70-220mm F3.5 Macro.
Add 1:2.5x magnification with a 3x magnification from the teleconverters to get 3:2.5x or 1.2:1!
So where’s the customary shot of all my Minolta-mount lenses? It’s not here, because there’s yet another I didn’t mention, and another on its way. This isn’t even the last of the geek entries, I assure you that.