Higher ISO and stopped down or wide open...

j-bo

This is a basic question and heck, I'm a basic guy but can't find the basic answer and it may be so basic that I'm embarassing myself asking.

I use the 70-200mm 2.8L. I usually shoot wide open at ISO 100 on sunny days and ISO 200 sometimes usually in Av mode. I shoot mainly motocross.

Is it better to shoot low ISO, fully open, or to increase ISO and stop down for the best sharpness?

If so, what range is the sharpest on the above lens?

Thanks.

gus

j-bo wrote:

This is a basic question and heck, I'm a basic guy but can't find the basic answer and it may be so basic that I'm embarassing myself asking.

I use the 70-200mm 2.8L. I usually shoot wide open at ISO 100 on sunny days and ISO 200 sometimes usually in Av mode. I shoot mainly motocross.

Is it better to shoot low ISO, fully open, or to increase ISO and stop down for the best sharpness?

If so, what range is the sharpest on the above lens?

Thanks.

Firstly i would stop down for greater depth of field rather than sharpness as 2.8 is rather shallow (depending of course on the distance you are from the subject)

I would have no issues at all leaving it at ISO 200 with a canon or even 400. So my call would be to close the lens down a tad & lift the ISO.

wxwax

I don't know where the 70-200 is sharpest.

I've read opinions that all lenses are sharpest at f8.

Almost certainly it's not sharpest at its maximum aperture (2.8)

But I pick my aperture based on what I want my shot to look like. If I want a blurry background, I open up. If I need more depth of field, I stop down. I'll adjust shutter speed and ISO as necessary. (Autofocus will typically work better with wider apertures.)

jdryan3

Most lenses are sharpest in the f/9-f/16 range. That said, I find my 70-200 f/2.8L IS to be sharp at f/4 and above.

RE: which is the best for you, I let my ISO be the last consideration. If I am shooting a moving object like a bike, I first determine how isolated I want it from the background (i.e. do I care if you can make out what is in the background). Since in that case usually not, I would shoot at f/2.8 - f/4. It also depends upon how far away I am. DOF may not be an issue if I am far enough away even at f/2.8.

Since it is a moving object, I would want the shutter speed to be at least 1/250 if not faster depending upon how fast the bike is, is it approaching me slowing down or away from me speeding up, etc.

So if I am shooting at f/2.8 to freeze the bike @ 1/500 or 1/1000, does the ISO I am using allow for a proper exposure (indoor motocross vs. outdoor road course)? I start at 100 and move up until I get it. That is the beauty shooting digital, especially with in camera histograms. I get immediate feedback and can adjust accordingly.

BTW - just my experience. I'm sure you will get many other very valid and conflicting responses.

j-bo

Okay great... I think now I know why some of my shots are soft or blurry, DOF. I usually shoot wide open all day long, even if I'm 40' away where blurred background wouldn't happen anyways.

I need to read more as I get confused on DOF. That chart that everyone says to look at is way beyond greek to me too.

As in good wide open:



Not so good wide open: So this one I would probably have been better off using F4 or F5.6 right? Exposure is a little off too, but just for arguments sake.

gus

Plenty of light there...try f4 or smaller. Bit trial & error depending on the days light but well worth getting it right.

Seefutlung

Typically, with sports, one trys to isolate the action ... hence a fast telephoto shot as wide open as possible. Assuming that your 70-200 is a Canon ... it is a very sharp lens even wide open.

Something like this-

127480398-M.jpg
F/2.8

Background detail, as a general rule, is very distracting in sports photography. So most pro sports photogs shoot wide open. You won't get as many keepers shooting wide open ... but the ones you get will be better.

My first consideration would be shutter speed ... the faster the better to stop action ... then lens length ... the longer the better for outdoor sports ... then ISO ... adjust for shutter speed, ambiant light and wide open aperture.

Gary

mercphoto

wxwax wrote:

(Autofocus will typically work better with wider apertures.)

Auto-focus is always done with the aperture wide open. If you have an f/2.8 lens it will auto-focus at f/2.8 even if you are taking the shot at f/8.

Motocross bikes are rather large objects and shooting them at f/2.8 will be challenging. Also your shutter speeds will be so high that they will stop all motion whatsoever, which isn't really good for motor-based sports.

Start reading up on the basics of a proper exposure. How aperture, shutter speed and ISO inter-relate to each other. What a change in aperture does to a photo, what a change in shutter speed does for a photo. You need this basic information to understand how you should be taking any individual shot.

j-bo

Start reading up on the basics of a proper exposure. How aperture, shutter speed and ISO inter-relate to each other. What a change in aperture does to a photo, what a change in shutter speed does for a photo.

Merc... this is what I wish to do. Do you recommend any good books that teaches in simple terms?

I so want to take photography classes or find a local club or something so that I can learn and ask questions to become better. Any ideas on how to find such things? I suppose I could go to the local photo store and ask them. I do know they offer a class, but it's more of how your camera works and using PS than the basics that you list.

Elaine

j-bo wrote:

Merc... this is what I wish to do. Do you recommend any good books that teaches in simple terms?

I so want to take photography classes or find a local club or something so that I can learn and ask questions to become better. Any ideas on how to find such things? I suppose I could go to the local photo store and ask them. I do know they offer a class, but it's more of how your camera works and using PS than the basics that you list.

The widely recommended Understanding Exposure by Bryan Peterson: http://www.amazon.com/Understanding-Exposure-Photographs-Digital-Updated/dp/0817463003/ref=pd_sim_b_1/103-0123621-9137462
is an excellent place to start. Also, you could look for classes at your local community college...I've taken 3 on-line classes through our local CC and they've been helpful.

Looks like you're doing a good job and will get even better with more practice and learning! Keep it up!

Elaine

jbr13

I got me DSLR to get out and take Motocross photos and have enjoyed in for a few years with my SLR-like point and shot. SOme tips I have picked up and gotten from pro mx photogs

My tips: Keep ISO down til you need to bump it up
Shot F4 and up
SHutter speeds of 400 and up, you want a clear shot, but you want to show some motion too. Set shuttter till you just are getting motion in the rear tire. IF you stop everything the bike looks pasted into the shot.

Shot from the inside or outside of turns.


Pro Tips

Try to get their eyes in the shot, see where they are looking
PEOPLE and SIGNage. These do make great backgrounds. I know in other areas they are a distraction, but in motocross the pro's like to have them in the background. Or that guy hanging over the fence waving his shirt or towel when his favorite rider or son goes by.


THis site has a good many pro MX photogs, and they post some real good stuff from time to time.

http://www.motonews.com/mototalk2/ Look around for shots in the Photo gallery and some in the MotoTalk forum

Transworld is good too

http://www.transworldmotocross.com/mx/


Pro photog sites http://www.cudbyphoto.com/main.htm

http://www.pbase.com/paulmerritt

http://www.alphado.net/ look down the center toward the bottom for MX stuff

Hope you enjoy and have fun.

Jason