Pixtus - Photography Forum, Photographers, Photo Tips

whaussies · **Dof -** 08-21-2006, 03:14 PM

This is a pretty simple question to most of you. For some reason I just don't have it logged in my little brain where it becomes a no brainer type of situation. I can control DOF when I have a lighted situation and understand it better. But I give you the following:

Low lighted arena and shooting very fast dogs. You have a 70-200 f2.8 lens. Camera wise you have to crank it to 800 iso to even start to stop the motion. Of course you want 2.8 to have your shutter speed as fast as you can. But this is where I loose it.... with that lens and focal length and dof. How do I get more dof to get the dog more into focus with those conditions? Close to the dog or farther and longer focus length. I think it is the second, but I need to have it stamped in my mind!

Thanks!!!!!

Bruce M. Morris · 08-21-2006, 03:42 PM

Heidi,
you will need to balance it out but you have 3 elements to work with:
1)with smaller fstop number- smaller Dof
2)Longer focal length-smaller Dof
3)closer distance- smaller Dof

Determine which ones HAVE to remain constant because of the shooting environment and then alter the others to get the results you want. Hope this helps.

srwatters · 08-21-2006, 03:50 PM

Your only other choice is flash. Even in a sports arena you can light the place up with high power strobes. I don't know what your relationship is with the venue, but perhaps some well placed 1000ws strobes will do the trick. Of course you'll need pocket wizards or some other long range wireless trigger.

Good luck.

whaussies · 08-21-2006, 03:53 PM

I would love to use flash, but the handlers feel it would mess up the dogs. 99% of the time it wouldn't but that 1% is the one that would complain the loudest! Or if the dog messed up for another reason, I would get blamed because of the flash! People want great pictures and then wonder why it is hard to get them in a darker arena!!

whaussies · 08-21-2006, 03:55 PM

Thanks Bruce that helps. Now to ingrain it into my mind. 1. is there. The other two needs to get there too!!

bondarnes · 08-21-2006, 05:12 PM

Would it be possible to set up some bright halogens just lighting the area where you want to photograph. The distance/focal length idea is basically a wash. It is a ratio and proportion calculation that remains almost constant if your subject image size is the same. When you back up you will get more DOF, but when you zoom in you will get less. Get a 1DS and you can zoom in PS There you wouldn't have to worry about DOF changing

engstrom · 08-21-2006, 05:12 PM

Assuming aperature and ISO are constant between the pictures with a long focal length from farther away and a shorter focal length from closer up then a longer focal length farther away would result in more DOF. I believe the relationship between focal length and DOF is linear but the relationship between subject distance and DOF is a square of the distance.

bondarnes · 08-21-2006, 05:24 PM

Scientifically correct, however the difference in real life is almost negligable (where is spelchek) very difficult to measure.

whaussies · 08-21-2006, 05:36 PM

The lights would be great, but doesn't work. I have tried to do something like that before and people freak. They think their dogs will freak so it is a major battle. I was going to do a halogen in one area and it just didn't work. End up making people upset. We are talking about 400 dogs running in two rings a day for three days. Usually I am in a building that has at least some light with sky lights or something, but this is in Ft Worth and this place just kicks me each year. I HATE noise, but I have to stop the motion. No win situation.

Don - go get a 1Ds sure thing! Hey I am close to you, I will just come and get yours!

Steelsun · 08-21-2006, 05:57 PM

I had to deal with the same thing when I did photos of a couple of dozen flyball races a few weeks back in Houston.
Lighting sucked (and was variable - dang halogens would sometimes read orange, sometimes blue, never white).

I settled for the following:
High ISO - 800 usually, but sometimes 1600
Low f/stop - usually 1-2 stops above 2.8 to get that good DoF
I also used a 70-200/2.8, and usually did it at a distance of about 30-40 feet.
Speed was a factor - the dogs are dang fast (it is a race after all) - I found 1/250 was often too SLOW for the action (unless it was on the bounce/turn at the box).

I settled for only doing one "point" per race - I would pick a particular point to stay focused on (say one of the hurdles or the box), and manually focus in to that point and get a feel for the DoF and when to trigger for a pic.

Steelsun · 08-21-2006, 05:57 PM

And your right about extra lights and flashes - they are usually forbidden by the racing authorities due to POSSIBLE distractions.

CaptainTom · 08-21-2006, 06:35 PM

Go to Ft. Worth Camera and rent a 20D or 5D, crank it up to 1600. PP with noise ninja, and be happy with the results.
If you need a hand at the show, give me a call.

whaussies · 08-21-2006, 06:43 PM

Tom if you are bored, you can always come by and show to ladies how to properly use their studio lights for what we need them for, by all means! HAHA I got tons of books but haven't had time to read them yet. We have a big show next month and I am tired of shadows:-(( We got decent lights but never really have been taught how to use them properly.

Oh and actually I am going to see Jeff on Wed. I might just have to rent a camera. With the money from this weekend I was going to put it towards a 30D.

Glen_A · 08-21-2006, 07:01 PM

here is a dof calculator that you can use to try and figure out what settings you need. http://bobatkins.com/photography/tec...ield_calc.html

CobyPhoto · 08-22-2006, 12:01 AM

I am with Tom, rent a 20D...you will be amazed at the quality of ISO 1600 images from that camera. One of my photogs uses that camera and his low light images consistently amaze me compared to my 1D Mk II's. That camera was made for impossible, low light situations, in my opinion.

CJ