I am debating another lens purchase and am seeking advice and recommendations.
My interest is primarily bird photography. My relevant camera bodies are Z9 and Z7ii. I also have the Z400mm f4.5 and the Z600mm PF. as well as the two Z teleconverters, 1.4 and 2x. I am happy with both of those lenses.
I have lusted after the Z 600mm f4 tc vr but that amount of money is not in my current budget.
I was considering buying a used f mount 600mm f4 E FL.
Would appreciate feedback and advice as well as any other recommendations.
I am wondering whats got you considering another lens.
a) your noticing lower light and F stop is becoming an issue for other than fair weather conditions.
b) the 600 F4 TC is overpriced or out of budget, perfectly honest, i wouldn't buy one i would just rent one as needed if even ever needed.
c) i would rent a 600 F4TC for a weekend, in fair weather i think you will be surprised of the outcome until you get into lower light or notice the Bokah of F4, F4 matters as does F2.8 more so for low light and micro detail and contrast.
d) Check the MTF charts i would go for a 400 F2.8 TC over the 600 at least you have the versatility of 400 F2.8-600 F4 range and the Tcs will compliment well, also above all your have F2.8 or with a 1.4 tc a maximum of F3.92, if you go with the 600 TC you out to F5.6 again.
e) the 600 F4 E FL is a F4 especially USED is very cheap now, again i would rent one and i think that when you experience all three lenses you will see there is a smaller difference optically in fair weather more a difference in lower light, but capturing at the source at F2.8 is amazing.
F) Rent Rent Rent, try before you buy as my girlfriend said when she met me LOL
I use F2.8 glass in zooms or primes or F4 primes in the 600mm range, many of my pro sports action shooter mates use the Z9 and the 600 FL F4 E and have no intention of buying the 600 F4 Tc...........they say its excellent but the difference and what they get its not worth it for them, that's not saying the F4 TC is bad in anyway its brilliant, just over priced.
Hope it helps
Only an opinion