| Latest Review Posted | SMC Pentax-FA* 300mm F4.5 ED [IF]
I've used this lens for over 10K nature shots. It is short for some birds but good for bigger ones and environmental portraits.
This lens is well-constructed and fairly light. The autofocus is not bad, and manual focus also works well. It is actually not difficult to manual focus with some practice.
This lens is decently sharp. The downside is that I usually have to use it at f/5.6 or greater to obtain acceptably sharp shots in the field. I have confirmed this with tests indoors with a sturdy tripod and the self-timer. The lens has some softness at f/4.5, even in the center. It gets better at f/5.6 and seems best at f/6.3 or higher. Whenever possible I use it at f/6.3. The softness at f/4.5 in the field is much worse, and I don't at all like the shots at f/4.5 in the field. In this way, the advantage of the f/4.5 aperture in the field is only for a bright viewfinder sadly.
This lack of wide-open sharpness makes this lens play poorly with the Tamron 1.4x teleconverter. With that teleconverter, even f/5.6 + teleconver = f/8 has some unacceptable softness. So, I would not recommend it with the teleconverter. With perfect conditions, the teleconverter enhances reach a little, but the advantage over cropping is negated mostly when you have to increase your ISO and you lose a little IQ.
Autofocus with this lens works but is not that fast on the K50. Perhaps it would be faster on the newer models. I can manually focus faster than the lens with my body. Continuous mode is really... |
