DOF which F stop

Chunkey Monkey

Chunkey Monkey

Suspended / Banned
Messages
355
Name
Mark
Edit My Images
Yes
I'm off to the Waddington airshow in a few weeks, I'm planning to use a 70-200mm F4 with a 1.4 extender. From what I gather I should be apr 100 to 150 yds away from the flying display and I don't have a clue what aperture to use to create a DOF wide enough to cover 130ft.
Can anyone who has been in a similar position advise me please.
 
Lancaster has a wingspan of 110ft and im sure there are larger aircraft flying ??
 
More important to get the shutter speed right if there air aircraft with propellers. About 1/125 works with a Lancaster (I'm only assuming there will be one there from Mark's post).


Steve.
 
Thanks that brilliant, I've only used this lens combination upto apr 15 yds and found dof very short, I know it improves the further away but hadn't a clue how much, that chart will help immensely.
 
Steve Smith said:
More important to get the shutter speed right if there air aircraft with propellers. About 1/125 works with a Lancaster (I'm only assuming there will be one there from Mark's post).


Steve.
Click to expand...



I'm aiming for higher shutter speeds than that as my stance isn't very stable, I suffer camera shake a lot :bonk:
 
mark2002 said:
I'm aiming for higher shutter speeds than that as my stance isn't very stable, I suffer camera shake a lot :bonk:
Click to expand...

If you are photographing aircraft with propellers, it's good to have a bit of blur on them.

A speed of 1/125 with a Lancaster gives about equal amounts of blurred propeller and clear space which looks about right.

A speed of around 1/500 and higher will freeze the propellers and make it look more like a model aeroplane rather than the real thing.


Steve.
 
mark2002 said:
Lancaster has a wingspan of 110ft and im sure there are larger aircraft flying ??
Click to expand...

All 110ft of that wingspan is the same distance from the camera if the plane is directly above.


I know you're unlikely to be shooting it directly from below, but I thought that'd help you understand how DoF works with large objects, ie a castle wall thats a mile wide but parallel to the camera would all be in focus with even the shallowest DoF. Stand a foot away from it and point your camera along it and you'll need a massive DoF to get it sharp along it's length.
 
...and at such a small aperture, diffraction would make everything equally soft rather than equally sharp!!! (However, that's probably beyond Talk Basics.)

Maybe a monopod would help you reduce camera shake to allow slightly longer shutter speeds?
 
Phil V said:
All 110ft of that wingspan is the same distance from the camera if the plane is directly above.


I know you're unlikely to be shooting it directly from below, but I thought that'd help you understand how DoF works with large objects, ie a castle wall thats a mile wide but parallel to the camera would all be in focus with even the shallowest DoF. Stand a foot away from it and point your camera along it and you'll need a massive DoF to get it sharp along it's length.
Click to expand...

Thanks Phil the distance ive quoted will be a side shot thats why im hoping to get the wingspan in focus. :thumbs:

Nod said:
...and at such a small aperture, diffraction would make everything equally soft rather than equally sharp!!! (However, that's probably beyond Talk Basics.)

Maybe a monopod would help you reduce camera shake to allow slightly longer shutter speeds?
Click to expand...

Thats now an option as ive just recieved a redsnapper RSF-284 and one of the legs screws of the create a monopod :thumbs:
 
mark2002 said:
Thanks Phil the distance ive quoted will be a side shot thats why im hoping to get the wingspan in focus. :thumbs:



Thats now an option as ive just recieved a redsnapper RSF-284 and one of the legs screws of the create a monopod :thumbs:
Click to expand...

From the side of a plane you can't see the wingspan, I'm confused:thinking:

Do you mean whilst they're flying? In which case, as above the greatest factor re DoF will be the subject distance, at 5000 ft even 2.8 will render the entire plane in focus.
 
Phil V said:
From the side of a plane you can't see the wingspan, I'm confused:thinking:

Do you mean whilst they're flying? In which case, as above the greatest factor re DoF will be the subject distance, at 5000 ft even 2.8 will render the entire plane in focus.
Click to expand...

I'm going to be at ground level parallel to the runway as the flying display planes fly down the runway at low level so i'm going to be side on apr 100 to 130 yds back so I assume i'm going to get the underside with wings showing [depending how low they fly) there will of course be frontal and rear shots as they approach and leave but they will be further away at this point so dof improves over the distance. Hope you see where I am coming from
 
mark2002 said:
I'm going to be at ground level parallel to the runway as the flying display planes fly down the runway at low level so i'm going to be side on apr 100 to 130 yds back so I assume i'm going to get the underside with wings showing [depending how low they fly) there will of course be frontal and rear shots as they approach and leave but they will be further away at this point so dof improves over the distance. Hope you see where I am coming from
Click to expand...

So wide open with the extender on (f5.6) you'll have a DoF of around 40 metres.:thumbs: Presumably with an extender you won't be shooting wide open (to get close to the sweet spot), at f8 you'll have nearly 60 metres to play with.
 
Also bear in mind you want to use your lens where its sharp as well as the right DOF i find on my 70-300 F8 is king most of the time.
 
I shot this Dakota with my 5D3 and Sigma 150-500 OS the other week as it flew by the house. I was a bit further away from the plane than I normally am at Waddington airshow but not much and it was taken at f/6.3 which is wide open for the lens.

8605618311_9d40e00a05_b.jpg
[/url][/IMG]

This one was taken at f/5.6 with the same lens at 283mm at Waddington last year and it doesn't look too bad IMHO regarding DOF anyway. That was from the front of the crowdline so should give you an idea of what you're likely to get with the 70-200 and 1.4x converter, although you have a crop versus this at FF.

7493953676_bb39126a74_b.jpg
[/url][/IMG]
 
If its a Canon 70-200 F4 then wide open with a Canon 1.4 extender still produces a very good image. Used mine last weekend to shoot some stationary birds and was amazed how detailed the shots were on a 5D3 even at 75% viewing. So if you have to use it wide open dont worry.
 
MatBin said:
If its a Canon 70-200 F4 then wide open with a Canon 1.4 extender still produces a very good image. Used mine last weekend to shoot some stationary birds and was amazed how detailed the shots were on a 5D3 even at 75% viewing. So if you have to use it wide open dont worry.
Click to expand...

My point about apertures was more related to DoF, ie the f4 with a 1.4x converter is f5.6 - so massive DoF at the required distance. And if the OP doesn't 'need' to shoot wide open, he will get improved IQ:)
 
Phil V said:
My point about apertures was more related to DoF, ie the f4 with a 1.4x converter is f5.6 - so massive DoF at the required distance. And if the OP doesn't 'need' to shoot wide open, he will get improved IQ:)
Click to expand...

Thanks again phil, I was planing on using wide open with the extender but as im new to this and by the sound of it f8 produces better IQ I shall aim for that. With a monopod even with my shaky hands Im should get something hopefully.

Thanks again Stuart for your offer to loan your extender thats really good of you, but as you may have gathered ive managed to secure the kencko pro 300 1.4x
 
Glad you've got your extender sorted, as you don't need it now I might try mine out on the wifes Sigma 120-400 OS f/4.5-5.6 as I've just got myself a Canon 1D MkIII and that AF's to f/8 and I've updated my 5D MkIII so it will do the same. Will also try my 70-200 f/2.8L IS MkII and 2x MkIII converter on my 1D MkIII to see how good that is compared to the Sigma and 1.4x converter.

As the light's still quite good I might just go and give it a go now.
 
thing is chances are you going to be shooting into the sky where all the light is :-)

light is good.
 
Changing the subject slightly )although I think you will be alright with your choice of lens) it's easy to think you need a longer lens than is actually necessary.

When the Lancaster flew down our way a few weeks ago, I took my 200mm lens thinking it would be o.k. but probably not long enough. With hindsight, I wish I had taken the 105mm as well - or instead.


Steve.
 
mark2002 said:
Lancaster has a wingspan of 110ft and im sure there are larger aircraft flying ??
Click to expand...

Don't even worry about it, it'll take care of itself. At air show distances with that lens you could probably shoot at f/4 (or f/5.6 with the 1.4 TC) side on and not have any massive problems getting the whole thing sharp as long as you're focussing on the fuselage. That said the lens will be sharper stopped down a little. I've used my 70-200L f/4 extensively for shooting aviation including air shows and generally run it around f/8 but I've never had problems opening it up a little from there.

Essentially, stick to f/7.1-f/9 if the light allows and don't think anything else of it. It'll be perfectly fine. :)

Steve Smith said:
Changing the subject slightly )although I think you will be alright with your choice of lens) it's easy to think you need a longer lens than is actually necessary.
Click to expand...

Absolutely, especially on APS-C. I use my 5D2 and 100-400L for the vast majority of my aviation shooting these days but I'm always amazed at just how close I can get with my 7D at 200mm. There isn't much in it between the two setups really!
 
Last edited:
Just a quick example, this is from back in 2008 but it was the first one I stumbled across! 1/250th was actually a little quick to get serious prop blur but this is 200mm on the 70-200 at f/6.3. You can see the depth of field extends a fair way in front as the markers on the taxiway are sharp, as is the ground behind. You won't have any problems getting the Lancaster all in focus at 280mm if you stick around f/7.1-f/9. :)

i0ZmEwA.jpg
 
You must log in or register to reply here.
Back
Top