# How do zoom shooters actually calculate their shots?

Started 2 months ago | Discussions thread
Re: How do zoom shooters actually calculate their shots?

Pixel Pooper wrote:

deednets wrote:

Pixel Pooper wrote:

With the same framing, you will get the same DOF at the same f-stop regardless of focal length. Changing your framing will change your DOF whether you do it by changing your focal length, your subject distance, or both. There is no "DOF issue" and you can use the same approach for shooting with a zoom as you would with a prime.

Ok, I play: at ff 85mm and 2 meters distance the dof is around 6cm at F1.8 and a touch less than 40cm at F11. 40cms typically gets all of a head in focus. So as long as I stick to 85mm I have a reasonably accurate idea as to what I am getting here regarding dof.

You will also get the same DOF at 50mm and 1.2 meters distance or at 200mm and 4.7 meters distance because the framing is the same. As long as you keep the same framing you will get the same DOF at the same f-stop, so a tight head shot requires the same f-stop regardless of focal length.

But on a zoom I have no strategy, apart from looking, what the dof is at, say, 110mm and F2.8. Tables help, but zooms have too many variables hence my question as to how people approach this.

The trick is to think in terms of framing. At a given f-stop you can't change the DOF without changing your framing. If you change your framing by changing your focal length or by changing your distance, the effect on DOF is the same. Whether you use a zoom or a prime, the only variables that affect your DOF are framing and f-stop.

I am aware of all this, have just been using a 16-35/4 Zeiss extensively by using the lens as an array of mainly 4 focal lengths: 16-20-24 and 28 mm. Never used the 35mm.

This is just the way I shoot, dialing in 20mm and then frame a shot and NOT standing somewhere and then zooming in to get my frame.

Spot the difference?

Deed

deednets's gear list:deednets's gear list
Sony RX1R II Fujifilm X-Pro3 Sony a7C Fujifilm XF 35mm F1.4 R Fujifilm XF 14mm F2.8 R +9 more
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