longer zoom which won

I am still looking for a longer zomm than my current 50 - 200 kit lens on my gx 10. I have discounted nthe tamron and sigma 70 to 300, as bothe seem to have questionable IQ and sharpness.

Can anyone rate the two lenses i am considering in terms of image quality.

pentax 70 - 300 FA
Pentax 80 to 320 FAJ

thanks for the help.

suds

you've got your designations backwards there.

I'm not sure if either of those older lenses is noticably better than the Tamron or Sigma APO in terms of sharpness. I would expect the FA 80-320 to be the best of the two Pentax's and being second hand it should be a fairly cheap option.

I presume your budget wont stretch to the newer DA 55-300, which is superior to all the above lenses in almost every respect.

The Sigma 70-300 DG was a dissapointment. Chromatic abberation was visible right through the range. When for instance photographing a zebra it came out black, green, white, green, black...instead of black, white... The APO version is a different ball game. Quality lens at a good price!

I think many would also question whether the Tamron's sharpness and IQ are worse than any of the Pentax lenses you've listed. The Sigma (non APO) definitely has the worst reputation of the 4.

You have the suffixes transposed.

The 70-300mm is the FAJ version and has no aperture ring.
The superior (IMO) 80-320mm is the FA version and has an aperture ring. This one can be a bit soft at the long end but is good up to about 260-280mm.

The Tamron 70-300 is pretty sharp, actually, although the Pentax 55-300 is said to be a generally better lens by its users (better contrast and less purple fringing, etc).