I have a question on Bokeh, DOF, or OOF

[shortie]

Hi Guys "n" Gals

I have a question on Bokeh, DOF, or OOF don't quite know the correct name for what I an trying to achieve

A bit of Background

I about 6 weeks I am going to shoot my little ones Xmas party (so have plenty of time to practice hence ask now and not at the 11th hour). The party is going to be in a local hall where lighting is not especially good (overhead fluorescents') and all the backgrounds are cluttered either windows where I can close the blinds, a stage one end and a kitchen the other.. One of the highlight of the party is a visit from Santa where each child is going to get a gift, this is what I need to shoot.

The hall is about 40ft square and the ceiling is approx 15ft high, so these are the dimensions I have to play with but bear in mind there will be a party going on as well so cannot upset the kids by stopping them having a run around and fun.

So I believe I need to take these shoots and have as much background blur to minimise and clutter but also have enough DOF to keep Santa and his little helper in focus.

My current kit comprises of the following

20D
18-55 Kit Lens
Nifty Fifty
18-200 sigma (I would have thought that this is way to slow for what I want great lens if you are outside and there is loads light)
Sigma ST 500 flash (Note not the super)
tripod

Possible purchases before hand

Canon 580 Flash
Sigma 24-70 2.8 Blah Blah

Now to the questions if you haven't got board already - :)


1. I am intending to seat Santa in a corner facing out so that I can get as much distance behind him with out effecting the party this will only allow direct straight on shots - IS this a good idea ?????
2. If I purchase the 24-70 do I get more blurred background at 24mm or 70mm with an aperature of 2.8 General type question, this will indicate how far away I need to be
3. Can I use the Sigma flash and a 580 as a slave, not quiet sure how it works but I think it is some thing like the 580 will fire when it sees the Sigma flash
4. As above but just have the 580 on the camera and use ETTL 2 to it's maximum
5. take all shoots using the tripod or go handheld for more versatility

That's about it - but if you have any tips please shout, also may have a chance to practice in the hall one week before the event

Thanks for reading this far

Shortie

[PhotosGuy]

1. I am intending to seat Santa in a corner facing out so that I can get as much distance behind him with out effecting the party this will only allow direct straight on shots - IS this a good idea ??
It should work, but the corner may make an annoying line in the pics. Will there be a tree?

2. If I purchase the 24-70 do I get more blurred background at 24mm or 70mm with an aperature of 2.8 General type question, this will indicate how far away I need to be
70mm, & 2.8 may not give you enough DOF.

4. As above but just have the 580 on the camera and use ETTL 2 to it's maximum
I'd shoot on "M", but that's just me. ;)

5. take all shoots using the tripod or go handheld for more versatility
I would use a tripod. Gives you time to watch for the kids expression.

...also may have a chance to practice in the hall one week before the event
Good idea. Do it, & good luck.

[Curtis N]

If I purchase the 24-70 do I get more blurred background at 24mm or 70mm with an aperature of 2.8 General type question, this will indicate how far away I need to beDownload this DOF calculator (http://boonecounty.info/photocalc.htm)(Excel-based). It will give you the field of view at various focal lengths and distances, as well as the DOF, so you can see the result of changing the focal length and adjusting distance to get the same FOV.

[shortie]

Photosguy

Thanks for the input - has made me think more on DOF instead of availible light

I have just been over to www.dofmaster.com as recomended here

And to get say a childs head and Santa's face in focus I would need a depth of about 9 inches, and from using their calculator it appears that at 7 feet and 60mm I would need f5.6 to get approx the correct DOF, this would suggest that my 18-200 could do the job if a 580 throws out enough light a 250/sec

Will have to have more of a play - looks like I goinng to have to get the 580 at least - sorry credit card

Shortie

[shortie]

Thanks Curtis N

Downloading now

Shortie

[PhotosGuy]

I would need a depth of about 9 inches Remember it's an ideal. Kids move! :D

[shortie]

I know

That is one of my biggest worries - what I could really do with is the new and improved Canon 690EX Flash which has the capabilities of 5fps to match the 20D

Buy hey I have a few weeks to practice and that is exactly what I intend to do

Shortie

[MattyB]

if i were you, i'd buy a 55mm (or is it 50mm?) f/1.8 prime, or even a 1.4 if you can afford it
and use that :D

the 1.4 is USM, so it's fast. and the f/1.4 will make for great DOF and bokeh :D good luck

[robertwgross]

Another thing to remember about shooting kids is to get down at their level.

The ordinary photographer shoots from four or five feet up at some little kid, and he ends up with a piece of floor showing directly behind the kid's head. Not ideal.

If you line it up right from about two feet high (below the kid's height), then you can get the kid with big Santa right behind him, and it just looks better.

---Bob Gross---

[Andy_T]

The nifty fifty should give you a more blurred background than the 24-70/2.8 ... but the bokeh may not the most pleasant one (depending on the background)

Do take some sample shots!

Best regards,
Andy

[shortie]

Thanks all

Andy / Rob / Matt thanks for the advice I think one of my biggest problems is going to be DOF but a few weeks to practice :oops:

I have the nifty fifty and have just received the 580 and 24-70 - 6 minutes ago and guess what left the cmera at home so that will have to wait

Also worked out how to make a mock up (one large teddy bear and one small ) so I can play at getting it right

Also thought of setting the laptop up and using remote capture any thought on if this is practical

Thanks again for the input

Shortie