I was about to sell my new Tokina/Kenko branded Pz-AF 2x Teleplus MC7 converter. I bought it new about $90.00 and I used it last with some reasonable moon shots with Pentax F* 300mm f/4.5. I don't have a reliable setup of tripod and ball-head and I test the same setup further in a birding tour with Don Edwards SF wildlife refuge. I brought along the setup and before I knew it, a Pelican fly by filling big part of my view finder and I take few shots hoping for a reasonable shot to convince myself to keep the TC.from the 600mm rig
1/1600 sec, 600mm, f/6.3, iso 1600, O Ev

the sharpest of the bunch with no editing
1/1600 sec, 600mm, f/6.3, iso 2000, O Ev


the 600mm rig kept me in a good distance from the birds




Impressions & Notes
- Not the best in IQ but very much hand-holdable setup that I can shoot without a tripod
- If you expect AF to work reliably, don't buy this TC as you may get disappointed. Though it has the power zoom contacts that look like the SDM contacts, it is not found to work with Pentax DA* 50-135mm f/2.8 in auto-focus.
- Though the TC worked with F* 300mm with AF, the motor noise and AF seem to take a long time to travel to focal point, I ended up shooting all birds flying shots in manual focus mode along with TAv where I set the shutter speed to a fast shutter as in 1/1600 sec and set Av to f/6.3, probably the lowest that is allowed after the TC is mounted.
- Unlike the time that I shot the moon with this set up, the manual focusing seem to work better than AF as I can get more responsive to the birds movement in MF. With the moon, the AF pretty much stay about the same spot not changing. With the birds, things around the birds as well as panning their movement kept the focusing to re-focus and somehow make the shot more difficult to do in AF than MF. Shame, I don't know how to explain it well, it is an odd feeling why MF works better than AF in this difficult shooting scenes with the birds.
- I had similar bad experience with AF on the F* 300mm f/4.5 without the TC that I divide my shots to have a balance between AF and MF subject to the scene and shooting conditions. There are many times that the AF foul up on me especially with AF.C and panning birds with distracting backgrounds or background with low contrast. And I can hardly rely on the semi-working AF for panning the birds movement.
- I am going to keep the TC as I find it worth keeping for $90 to bring my 300mm into a workable 600mm lens. Of course, there are many cons that go with the TC approach in degradation of IQ. My approach in assessing the usefulness on the TC is making the shot with compromises and the TC does let me stay at a good distance in not disturbing the wildlife.
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