Tamron SP 500mm F/8 (55BB) Mirror Lens

[Lloydy]

[sammo]

Michael - I disagree, coal has an albedo of about 0.1 and Moon I read that is less (0.07). Maybe the 0.12 figure is overall, on the whole sphere, counting also the "dark" side, which is accualy a lot brighter. But this doesn't make a difference to the conclusion that overexposing two stops compared to a sunlit scene on Earth is the correct exposure

I have to try out my 55BB as well to see what it can do.

[mo]

Lloydy, that is a shame.... oh well there is always next time and it may be at an even better price..

[cooltouch]

Well I dusted off my 55BB and took some test shots today. Nothing spectacular about the photos. But they are good representations of what the lens can do, I think. I must say, this is the best mirror I've ever owned.

This first pair of shots is of a water dispensing kiosk about 400 meters from my house. I have come to use this kiosk as a test for my telephoto lenses, 300mm and longer. The text "We care about the water you drink" is what I focus on, and I use this to judge lens resolution. Compared to my other teles, I would rate this Tamron 55BB as one of my very best. The slight distortions you see in the text is caused by heat convection currents. It was hot today.

First a reduced image of the entire shot of the kiosk:


Then a 100% crop, showing the text.


Next is a fire hydrant, about 100 meters from my location. I focused on the numbers stenciled onto the hydrant. The first photo is a reduction of the full image. The second is a 100% crop.



Now to try the 55BB's close up capabilities. The reduced, uncropped photo followed by a 100% crop of the oak leaf.



And the last one, another close-up. The left side of my old BMW R90/6 motorcycle's engine.



It's been a while since I've taken photos with such a long focal length. My DSLR handles higher ISOs so poorly that I almost never shoot at an ISO higher than 100. Keeping the shutter speed up was a real challenge. Today was a day with scattered clouds and a pronounced breeze. So every time the sun would duck behind clouds, the shutter speed would plummet. And if a breeze was blowing, it would cause either my subject or my camera to shake, sometimes both. And I was using a stout tripod, but with such a long focal length, even a stout tripod will exhibit tremors. Initially I was trying to photograph some flowers, but I gave up after about twenty attempts and settled on more stationary subjects. I also found that if I focused just using my Mark 1 eyeball and the viewfinder, even if the subject looked plenty sharp, often the focus was just a tad off. Using Live View at 10x provided me with the precision I needed to nail focus.

[tomzcafe]

Not sure whether mine is just slightly younger, but on the lens read BBAR MC

[parabellumfoto]

[cooltouch]

I bought a Samyang mirror a while back -- the 800mm f/8 mirror. I was very disappointed in it. It was incapable of delivering acceptably sharp photos, so I returned it. But I think that I just got a bad copy. Because I've seen some excellent photos taken with the 800/8 Samyang. I was considering buying another when I fell into a deal on this Tamron 55BB. Since I knew how good the 55BB was from previous reports and images here at this forum, I was confident that it would be good. I had a 30-day return privilege on it, so I wasn't worried.

So anyway, as for the Samyangs, I've heard that the 500/8 is just okay, but that the 500/6.3 and the 800/8 mirrors are excellent. Apparently Samyang has some issues with regard to consistency, though, so be sure to buy from a source that offers a satisfaction guarantee so you can return it if you got a bad copy.

One thing I really didn't like about the Samyang, and it would have been a problem even if it wasn't optically compromised, is the focusing collar only turns through 90 degrees as I recall. The 55BB's is almost 360, if I'm not mistaken. 90 degrees is way too short of a throw when you're trying to nail focus with such a narrow depth of field. I really like the extra rotation that the 55BB provides.

[parabellumfoto]

Thanks for the detailed reply. In time I may buy a 500mm Samyang just to try it out. The information has been very helpful.

[hoanpham]

still i think the tamron 55BB could have even longer focus throw.
midrange is good to focus, but from 80-100 meters and longer it still very difficult to focus.
dof is razor thin at 80 meters.

[cooltouch]

Heh, at first I thought the 55BB's long focus would have been plenty. But when I was actually out giving it a workout yesterday, I was surprised at how just the tiniest adjustment -- couldn't have been more than a few minutes of arc -- would bring the image from sharp to fuzzy, and vice versa. So, yeah, it would be nice if the focus throw were even longer. But greater than 360 results in problems wrt the scale on the lens.

[awa54]

I recently picked up a decent copy of the 55BB and I'm impressed with the images I'm getting, both at long and short subject distances. I'm also pretty satisfied with the contrast in the images, my copy doesn't really leave a lot on the table in that respect when compared to any other sub $1000 long teles I've used.

I do have one gripe though... when I shoot it on my Sony a900, the Sony's JPEG engine insists on making the images look overexposed, not just a little either, like 1 to 2 stops, then when I look at the RAW files from shots that I've exposure compensated to produce good looking in-camera JPEGs, I have to compensate the exposures by... you guessed it, 1 to 2 stops over to get correct tonal range back. Has anyone else experienced this quirk when using the 55BB? (or other mirror lenses)

DSC07898 by David Wimmer, on Flickr[/img]


DSC07883 by David Wimmer, on Flickr


DSC07875 by David Wimmer, on Flickr

[Olivier]

[Focusthrow]