Now i've got the possibility of getting a Pentax 50-135mm f/2.8 for a very good price secondhand : €500
I could also buy a Tamron 70-200mm f/2.8 for : €450 .
I'm looking to change my 55-300mm f/4-5.8 for something much sharper , i mainly shoop portraits but i would also have to find something with a longer reach for shooting on circuits ... motorbikes.
I know that the 50-135mm will be better at AF and a little lighter too but the Tamron 70-200mm will give me longer range and by what i have read so far , it's very sharp.
I could take the 50-135mm now and later buy a 200mm f/2.8 or 300mm f/4
I could also take the Tamron 70-200mm and use a teleconverter to get to 300mm f/4 ?
Mmmhh difficult