[SParker48]

Has anyone had experience with this TC and Pentax zoom lenses? I have a 55-300 and would like to extent it a little. I am wondering how much is lost with this TC. I had a Quantaray TC and was not happy with the results. I would appreciate hearing others experience with the Kenko 1.5 . Thanks.

[jimH]

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[Marc Sabatella]

All TC's work the same way in term so loss of light - one stop for a 1.4X TC, two stops for a 2X, etc. While some combinations of zooms and TC's will produce better results than simply cropping, that is seldom true of consumer grdes TC's and lenses like the ones you are asking about. I'd expect this combo to work noticebaly worse than cropping. Some people have reported some success with similar combinations, though.

Since this is about lenses, not cameras, I'm moving the thread to the propert forum.

[BillM]

Hi S,
Assume your copy is DA not DA-L, little or no difference optically though I guess.
Havent tried kenko,but have tried others,bought used promstr 1.7x @ 30$
to be honest, wish I bought circular polarizer or extra battery instead.
Youll lose most hand-held opps, in addition to IQ suffering.
Something that comes to mind, if your interest lies in lengthened reach,
is a mirror lens, be better in IQ (my opinion) at about same speed as
55-300/TC stack. Could probly pick up descent 500/f8 mirror for half the price
of that kenko new.

[SParker48]

Thanks, that really helps sort through the hype.

[SParker48]

I know nothing about mirror lenses, can you recommend a few?

[Marc Sabatella]

See the Mirror Lens Club thread in this forum for tons of examples from a variety of mirror lenses. The only ones available new are the Samyang-made 500/8 and the 500/6.3 (not sure who makes that); both are sold under a huge number of different names, but they are all the same two lenses. Both are fairly mediocre; the f/6.3 version is probably a bit better. The better mirror lenses (like the Tamron that many rave about on that thread) are long discontinued, but if you hunt on Ebay, you may get lucky.

[andre-mz5]

The Kenko Pz-AF TC is one of the few which support SDM and also the loss in IQ quality is minimal in combination with a good lens. Below some test shots from K7 + DA*300 (+Kenko TC) to get an impression. Of course the DA*300 is in another league compared to your 50-300, but if you can find the Kenko it is worth to try it out.
Pictures taken from tripod wit SR off. Av mode at F5.6 and ISO 100
1 - DA*300, no TC


2 - DA*300, no TC, 100% crop


3 - DA*300 + Kenko TC


4 - DA*300 + Kenko TC, 100% crop


5 - DA*300, no TC, cropped to match with 100% crop of TC for comparison


Hope this gives you a good impression.

[JeffJS]

See the Mirror Lens Club thread in this forum for tons of examples from a variety of mirror lenses. The only ones available new are the Samyang-made 500/8 and the 500/6.3 (not sure who makes that); both are sold under a huge number of different names, but they are all the same two lenses. Both are fairly mediocre; the f/6.3 version is probably a bit better. The better mirror lenses (like the Tamron that many rave about on that thread) are long discontinued, but if you hunt on Ebay, you may get lucky.

It's worth Noting that the Tamron is also an Adaptall lens that requires an adapter for each different mount type to use. If all you intend to use it for is the 500mm mirror, then any suitable adapter will work and can be had for an extra $20. If you want to play with the Other Adaptall lenses, you may find yourself paying a lot more for the adapter. If you're going to seek out a Tamron on Ebay, figure on paying $150-$300 for it (the price varies wildly), and set your search for a Tamron SP 500mm. Figure on changing the mount, and most important, Make sure there is NO fungus on the mirror.

Many of the others are T mount lenses that again, require a separate adapter.

In either case, note that the mirror 500mm lenses are typically Fixed aperture and to control light (if you want longer shutter speeds), you are placing Neutral Density filters in the Rear of the lens. That's true with any lens but in the case of Mirror lenses, can be particularly annoying. I note it however, because some of these lenses are supposed to come with them. Make sure they are there. They are 30.5mm threaded filters. Usually there is an ND2 and an ND4 or something like that. ALSO, note that with most of these rear filter lenses, A filter has to be in the rear of the lens. I don't know Why that is, but it seems to be the case.

Good luck...

PS.. Comparing a DA*300 to a 55-300, it really not a fair fight (see sig ) IMO...