Beginners guide to depth of field and f stop

[ChrisRidley]

I wrote this article for a guy who emailed me a couple of nights ago - it's on my blog page:
Thought it might help someone

 

[kittymaguire]

Hi Chris

I think that you also need to mention that the distance between the subject and the lens also has an effect on depth of field. Also that the depth of field will also depends on the focal length of lens being used.

 

[Helen B]

Chris,

As the intention of it appears to be to introduce the basic relationship between depth of field and f-stop it looks pretty good. Maybe a simple diagram or two would be worthwhile.

With introductory texts like this there is the danger of providing too much information, and depth of field is one of those subjects that can get very complicated for a beginner - the relationship between distance, focal length and depth of field is not easy for everyone to grasp. In fact there are plenty of examples of misinformation on the web about things like DoF being greater for shorter lenses than for longer lenses (it usually isn't, for the same size of image). Simplification can lead to incorrect ideas being spread around. It might be worth giving a link to a separate, more in-depth article, written by yourself or already existing on the web.

If there was one point that might be worth adding to a basic text, it is that diffraction can rear its ugly head. There is a recent thread about the mess that diffraction makes here. That middling level of detail would be inappropriate for absolute beginners, of course.

Best,
Helen

 

[EOS_JD]

I wrote this article for a guy who emailed me a couple of nights ago - it's on my blog page:
Thought it might help someone

Chris. This is too basic. There's a little more to it than this.

You didn't mention the subject distance or even more importantly the focal length! With a long lens even with a small aperture you may have a very shallow depth of field. If you shoot a subject with a large aperture you can still retain everything in focus if it's at an appropriate distance and you are using an appropriate focal length lens.

Also you didn't mention the effect that aperture has on exposure although I appreciate that may not have been required for this point.

When someone asks me, my first advice is to purchase Understanding Exposure which explains this.

Remember that there are 3 things that affect your depth of field. Focal Length (magnification), distance to subject and aperture.

try this

 

[amateursnapper]

Hi Chris, i wrote a similar article on my site a few weeks back. As has been mentioned above, I think it's important to mention that depth of field is affected by more than one factor, not just aperture size. But I'll admit it's a tricky subject to cover comprehensively when you're trying to aim it at beginners.

Pete

 

[terri]

Guys, I've removed the links to your personal articles. Please keep in mind we have an "Articles of Interest" forum and you are welcome to submit any articles to me that you'd like to see published here. All articles have to be reviewed by TPF Staff prior to publication for content accuracy - thank you.

Terri
TPF Editor

 

[EOS_JD]

Chris
I also had a look at some of your "tutorials". I appreciate that your guides are directed at beginners but providing the right information is vitally important.

There is some misinformation and too much missing information for your tutorials to be of real use and may cause confusion to a beginner when they realise there's more info required.

It's great that you are trying to provide the info but it's best if that info is correct.

i always advise buying Understanding Exposure as it explains all details relating to exposure - shutter speed, aperture, ISO - in detail that is easy for a beginner to understand.

 

[ChrisRidley]

Sorry I havn't responded to the comments - it's only because I didn't actually get notification of any replies, I thought I had made sure I clicked the notify button when I posted. I'll check it as soon as I can. If I had seen the comments I would have done something. Crossed wires here.

I will edit/change my article with regard to your comments, but as my article links have been moved/changed/deleted so there seems little point re-posting the links again.

 

[don farquhar]

Here is perhaps a better dept of field calculator
http://www.dofmaster.com/dofjs.html

 

[jsmharley]

I purchased the Understanding Exposure book that is so forcebly recommended on here and have to say Thank You to everyone who has ever mentioned it. Awesome book, I am now using my camera in Manual mode and have a little more confidence doing it