DOF difference: f2.8 vs f4?

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payal_choksi

Well-known member
hi all,

i will be getting canon 5d mark iii but am really confused about the lens. should i go for canon 24-105 f4 or tamron 24-70 f2.8. Till now i was bent on going for tamron but the canon has extra reach.

is the difference in dof very large between f2.8 and f4? i will be using the lens purely for video. i will be shooting documentaries and corporate videos and interviews.

pls help me out if you have examples of the difference in the dof between f2.8 and f4. your views and answers will also help me.

which one should i go for?

pls pls pls help me

regards,

payal
 
 
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I think f4 will give you little enough DOF on a fullframe sensor for most shooting

Of course a little more light can help

Personally Id take the longer reach esp for interviews and the like because you can change framing while rolling..

S
 
this is getting very confusing choosing the lens. tamron has 2.8 canon has extra reach. will the shallow dof on tamron be more pleasing than f4 on canon? will i get good shallow dof on tamron?
 
The 2.8 will look marginally nicer but have significantly less reach - you choose - Id take the reach

Consider that many movies are probably shot no wider than F2.8 on an S35 chip - that is the look you get with a fullframe chip at F4

S
 
I had the 24-105 for a while and sold it after renting the Tamron 24-70. 2 reasons - much quieter (silent) IS on the Tammy, but more importantly, the Tamron was much sharper @ F/2.8 than the Canon was @ F/4.
 
id get the Tamron, solely based on the fact that its faster and sharper.
Although, i think what most people are missing... is what style of shooting is YOUR style?
I shoot mostly Weddings and event as well as interviews. I prefer wide shots and detail shots, therefore I use mostly standard zoom lens and primes since i do a lot of camera movements.
I find using super zooms beyond my 50mm (i use a GH2 crop camera, so thats nearing 100mm) almost impossible to stabilize and limiting with regards to the type of story telling I do.
Most of what I use on my x2 crop camera: 14mm f2.5, 35mm f2, 24-70 f2.8, 14-50 kit, 15mm fisheye. I work with a shoulder rig, glide cam, glide track, and sometimes tripod/monopod.
Look online with regards to the type of shooting style you'll be doing, and figure out what zoom range you would like to emulate.
 
Don't get confused. The DOF is a bit shallower @ 105mm and f=4 rather than 70mm and f=2.8 !
So I would not focus on shallow dof.
The f=2.8 is one stop brighter (maybe even 1.5 stop, since the 24-105 is a bit darker than it should be) so you can work with less available light.
But personally 24-70 is too short for my taste. Hence I have opted for the 24-105 as an all around lens for photography and video.
If you shoot stills note also that I have found the Tamron marginally slower to autofocus.
Considering that you can find the 24-105 in the used market for almost half the price of a new Tamron 24-70, and considering the longer reach of the Canon lens, for me the choice is easier. But, consider also that I have found out that there is quite a sample variation for the 24-105. You have to check the lens you are getting and test that it is sharp even at f=4. Two samples I have tested where very different in sharpness wide open.
But if you are ok with the reach of the Tamron and have the extra cash, it is an excellent lens that would give you one more stop of light.
 
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