Changing distance settings

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rasmusrok1

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Name
Jonny
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Hi

I have recently acquired (thanks to rusty) the understanding exposure book, and really enjoying it!

I have a quick question:

In the storytelling apertures section, i understand that for a large depth of field you must use a greater Fstop (i.e. f/22) however it talks about changing the "distance settings).

How do you change these settings, i have a sony alpha a300. I cannot find these settings to change. it is to preset the depth of field.

Am i being dumb or can my camera just not alter these settings?

Thanks for the help

Jonny
 
If you look on the barrol of your lens, you will see the distance settings, these are for when your using manul focus. If you are using a small apeture you can simply set the lens to infinity (Looks like an 8 on its side) and snap away knowing the whole shot will be in focus.
 
If you look on the barrol of your lens, you will see the distance settings, these are for when your using manul focus. If you are using a small apeture you can simply set the lens to infinity (Looks like an 8 on its side) and snap away knowing the whole shot will be in focus.
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i cannot find this mark on my lens! i dont think my a300 kit has it!
 
aaaahhh this is going over my head lol! I just cant seem to find out how to change the distance thing at all. How do i change it i.e set it to infinity? Its not on the lens i dont think!
 
A lot of modern lens do not have the distant markings any more But if you do you set infinity at the F number you will have all in focus at its max for that F-stop
There was a time when you could measure from your film plane (its marked on the body with a circle with a line through it) to subject and set the lens to this distance, some lens have distance on but not the kits lens or cheaper ones.

Another thing missing now is the red make for IR focus and this is different to white light so you have to adjust the focus for IR work
 
A lot of modern lens do not have the distant markings any more But if you do you set infinity at the F number you will have all in focus at its max for that F-stop
There was a time when you could measure from your film plane (its marked on the body with a circle with a line through it) to subject and set the lens to this distance, some lens have distance on but not the kits lens or cheaper ones.
Click to expand...

Sorry for my noobness but how do you set to infinity at the F number? Is that just setting the F number to F/4
 
There is some serious misunderstanding going on in this thread.

The 'distance' scale tells you how far it is to the thing the lens is focused on. Now the depth of field will vary depending on that distance and the aperture size (and other things but lets keep it simple).

Setting the distance to infinity will set the lens focus to infinity, which will not have everything in focus and as Steve has pointed out will waste half your focus.

the depth of field scales seen on manual lenses give an indication of the distance to either side of the focal distance that will be in focus.
On prime lenses the scale will be just points. On zoom lenses you will get a curved line.

If you want the maximum amount of your photo in-focus then read up on hyper-focal distance.

I'll come back later with some pics of dof scales and a decent linky to hyperfocal distance.
 
If you look at this old lens you see on the barrow the markings you will se colour markings what are matched on the F-stops you set the infinity mark to the colour mark same as your F-stop on the left and the same colour on the right will show you how far is still in focus for that f-stop
Hope this helps
35mm-f28-aid-KEN_3859-460.jpg
 
Just to add to the above post. As the lens is shown, at f16 (blue marks) everything from infinity to about 10' will be in focus.

If you now rotate the focus so the infinity mark lines up with the blue mark on the left, the blue mark on the right will line up with about 5'

At that setting, everything from infinity to 5' will be in focus.

Basically, wherever the focus ring is, the two distances which corrospond to the two coloured marks for whichever aperture setting you are using are the near and far points of focus.


Steve.
 
I'm not sure you understand this Chas.

Yes, the coloured marks indicate the dof that you will get with different apertures. However putting infinity at the central point will not maximise your depth of field.

Assuming you're taking a landscape and want infinity in focus and as much of the rest as possible, then the infinity mark want to be lined up with the left most marker for the aperture that you are using.

So in this case if using say f/8 (which is in pink on the scale), the infinity marker should be over the pink vertical line marker (just to the left of the red dot). The depth of field will then cover the distance between infinity (at the left marker) and around 3 meters (whatever lines up with the rightmost pink marker.

This particular lens is a wide prime which has a fairly short infinity focus which to some extent disguises the way that using infinity at the central point is wasting dof. Look at a longer lens and compare.

*Arghh Steve beat me to it.*
 
who? said:
I'm not sure you understand this Chas.

Yes, the coloured marks indicate the dof that you will get with different apertures. However putting infinity at the central point will not maximise your depth of field.

Assuming you're taking a landscape and want infinity in focus and as much of the rest as possible, then the infinity mark want to be lined up with the left most marker for the aperture that you are using.

So in this case if using say f/8 (which is in pink on the scale), the infinity marker should be over the pink vertical line marker (just to the left of the red dot). The depth of field will then cover the distance between infinity (at the left marker) and around 3 meters (whatever lines up with the rightmost pink marker.

This particular lens is a wide prime which has a fairly short infinity focus which to some extent disguises the way that using infinity at the central point is wasting dof. Look at a longer lens and compare.

*Arghh Steve beat me to it.*
Click to expand...
Read what I put again I said set it to the mark on the left This is NOT my lens but one I found on the web
 
hmmm so on my kit lens for the alpha 300 there is no infinity symbol so does that mean i cant change my distance to infinity, i understand how the distance corresponds whith the DOF i just dont know how to change my distance settings!

thanks for all the help guys!
 
Chaz Photos said:
Read what I put again I said set it to the mark on the left This is NOT my lens but one I found on the web
Click to expand...

You are quite correct. I mis-read your post.

Abject apology offered.
 
this is starting to make a lot more sense now thanks everybody for being sooooo helpful. I will read all the material you guys have put links to. Thanks again! I think i am ready to post some shots soon!
 
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