how to use a Tamron 500mm mirror lens

I just got me a 2nd-hand mirror lens for use with my K-7. I was under the impression I only had to set aperture to F8 and shoot. Alas, no. The LCD screen shows F---- and the camera refuses to take the picture in any mode. Does anybody know of a work-around for this?

Grts
Hendrik

thks. I wasn't aware of this menu-item

For a single aperture lens such as the Tamron mirror, there is no need to enable the aperture ring (there isn't one) and the viewfinder will always read f-- whatever you do.

However, you can still use the camera in Av mode, and it will meter in any case (the same as it would with a normal lens when it is wide open, which effectively is what the Tamron always is). You may find a little bit of exposure compensation may be required, so check the histograms etc after you've taken a few test images.

I have one of these lenses and they are capable of very good results when used with care. A few hints (sorry if this is all old hat):

(1) always use the lens hood in order to maximise contrast with mirror lens

(2) shoot RAW not JPEG to give best file to work with afterwards

(3) avoid scenes with bright highlights close to your subject/in the background - as these are the ones that are most likely to give you the characteristically busy mirror lens donut bokeh

(4) do not be tempted to hand hold it unless you are very steady! I know it is small and compact but your percentage of truly sharp shots will not be great unless you up the ISO to get fast shutter speeds.... not something you really want to do with the K-7

(5) instead, I recommend using it with a lightweight monopod, and leave the shake reduction switched on. This works for me very well - down to about 1/125 second at a push - with a Manfrotto Modo monopod that cost around £20

(6) the "catch in focus" feature that Pentax (and Nikon) offers, can be very handy with the mirror lens - as long as your subject is in the centre of the frame (more likely with a very long lens than with a wide angle). For this to work, you need to ignore Cardiff Gareth's advice above!! Instead, leave the camera in AF and the lens marginally out of focus before taking the shot. Next, press the shutter and then very slowly fine tune the focus of the lens.... as soon as you get it bang on, the camera will take the shot.

Hope this lot helps. Many people give up on mirror lenses, and they certainly have their quirks and drawbacks. But used carefully and with the right subject matter (which basically means "not moving" and "not close to anything that might cause nasty bokeh"), they can really deliver. And there is nothing else to compete at anything near the same price.

Cheers,

Jon

IIRC if you son't enable use of aperture ring then the camera will not fire, even with a fixed aperture mirror lens.

Oops sorry, absolutely right. Other than that, I think the rest of what I posted still stands though! And to whet your appetite, here's one of my Tamron shots:





Jon

Indeed. Can I leave "aperture ring enabled" on all the time?

rgds
Hendrik

Yes, there's no problem leaving it activated.

Jon. Does all this advice also apply to the pentax 400-600 lens. I always use a tripod but am somewhat nervous of this beast.
regards thoramay

The Pentax 400-600mm needs activation of the aperture ring to work. Now the aperture changes on this lens, despite it being a fixed aperture physically, simply because it zooms whilst the glass of course remains the same size. It's an optical effect.

Hi Gareth - absolutely agree with you for most MF primes, but the Tamron 500mm can be a pig to focus when you don't have a nice bright full frame viewfinder! At f8 the viewfinder isn't exactly bright, and the depth of field is miniscule. I find the camera does a better job than me most of the time with this particular lens, but I don't bother with catch in focus when using more "normal" primes, for the reasons you state.

Cheers,

Jon

I think it probably would... I've seen one of those lenses once, and it looked very nice (if rather out of my price range when you get one in good nick!). Oddly enough, I think it was Daniel from this forum who used it handheld and got a half way decent shot! I think the bottom line with long mirrors is to use slowly and with care, and I suspect the Pentax 400-600 is capable of providing excellent results.

As regards manual focusing, I have found that using a katzeye split screen has utterly changed how I use my K20 and hugely improved my percentage of in-focus shots. I'll readily opt for manual focusing now whereas with a standard blank screen I'd prefer to gamble with the AF. I wish I had bought one much sooner, a very worthwhile investment.

K.

I've got some good results with my 500 mirror at a motor racing event. Moving is fine as long as its predictable, Focus carefully in advance & wait for the action to reach that spot. (The green hexagon helps confirm focus even in MF)

Certainly I found when someone came off into the gravel, they rapidly moved out of focus - I've got a rapid sequence of a sidecar spinning off into the dirt, which is somewhat let down by getting progressively softer

DOF can't have been more than about a handful of meters, judging by some of the pictures of the pack coming round the bend...