Sigma 120-300 f/2.8 vs Sigma 100-300 f/4

Hi All

I am in two minds over a repalcement for my Sigma 70-300 APO lens. its too soft at the long end without stopping it doen silly amounts which means that i get very little bokeh and i have to have very good light as well.

my kit also consists of:

sigma 17-70 f2.8-4.5
canon 50mm f1.8

ordered kit is

sigma 150mm Macro
canon 85mm f/1.8

my question is which lens to replace my 70-300 and does the f/2.8 warrant the almost extra £800 pounds for it. If the IQ is substantially better than the f/4 then it could become a possibility. I will be planning on using it with a 1.4X converter as well.

any thoughts on this - is it worth saving the extra £800 or should i stick with the f/4

so far pros for the f2.8:
extra stop of light
better DOF control

pros for f/4
cheaper
lighter
bigger range of focal length.

help please.

Depends on what you shoot and the light you shoot in.

Here is the thread on the 120-300 I added a few myself in the last few days. https://photography-on-the.net …php?p=5819136#p​ost5819136
I have never held or used the F4, but take it from me the 120-300 2.8 is seriously heavy.
All my shots are hand held, but after using the body and lens for 4 or 5 hours you feel it.
One comment, again I know nothing of the F4, but the 2.8 is very sharp even at F2.8, and expose it right you have a wonderful shot that needs little pp if any at all

Cannot comment if it is worth the extra, if you can afford it it is for sure, but I would never sell the 2.8 version

Also I bought mine from Digital REV it was a little over 1k delivered, though since the exchange rate has change some what and now they cost more

I will be using either with a monopod to reduce the weight bearing on me.

I will be using it for event photography and where the 70-300 didnt give decent shots as the speeds where rather low as the light is not always the best.

Other uses will be wildlife/birds. hence the reason for the 1.4 TC so the need of a fast lens both in aperture and focus is needed.

33L wrote in post #5819347
I will be using either with a monopod to reduce the weight bearing on me.

I will be using it for event photography and where the 70-300 didnt give decent shots as the speeds where rather low as the light is not always the best.

Other uses will be wildlife/birds. hence the reason for the 1.4 TC so the need of a fast lens both in aperture and focus is needed.

No probs there you will get decent shots for sure.
I have used a TC, not that happy with it, Focusing gets more erratic, but many have and do use them with great results.
The 120-300 is very fast focusing as well

The f4.0 is a superb lens and from all reports is very close to or matches the 2.8. I owned the 4.0 and rate it highly. I can't speak about the 2,8 but I do know it to be excellent too as I have researched it with view to purchase in the past. with the 4.0 my own experience is that it needs a monopod to consistently get the very best from it, i.e. 9/10 rather than 8/10 and it also helps with the weight and length. So really it comes down to if you need the extra light. With a 1.4x the AF is still very good and so is the IQ, but you are then at 5.6 of course. I'd only get the 2.8 if I knew I needed that aperture and had faith it would be sharp wide open.

i had the same dilemma last week, i went with the 2.8. I need the faster glass, and the ability to go 2x and get 600 @ 5.6

got an example at 600 f/5.6
im might not ever need it but it would be nice to know!

120-300 @ 300mm 1/320th f2.8 ISO 3200 1dmk3

120-300 f2.8 with 2x tc 600mm

33L wrote in post #5819250
my question is which lens to replace my 70-300 and does the f/2.8 warrant the almost extra £800 pounds for it. If the IQ is substantially better than the f/4 then it could become a possibility. I will be planning on using it with a 1.4X converter as well.

any thoughts on this - is it worth saving the extra £800 or should i stick with the f/4

I've owned, used, tested both of these (fine) lenses. Is the IQ substantially better with the f2.8 lens? NO. Is the IQ slightly better? Maybe, maybe not. They are both excellent optically and comparable in my own findings. I found the 1-3EX to AF slightly quicker, and even though it's somewhat heavy to lug around, it isn't anywhere near as heavy as the f2.8. If you plan to use a 1.4x a lot, I would say get the f2.8 lens. If not, and if you want fantastic IQ in a smaller package, get the f4 lens. Again, both are Sigma top-class lenses.