canon rf 100-500mm f/4.5-7.1l is usm lens, please explain, setting focal distance range

[ahardy]

I have they canon rf 100-500mm f/4.5-7.1l is usm lens. Can someone explain the  "settng focal distance range".

I am photographing wildlife ie moose, bears, wild horses. I am having trouble with clarity of the animal at a distance. I read the manual and I'm still not sure if I should use "full" or "3 meters to infinity". I had it on the latter, and feel like thats not working. I have been on a good tripod, and hand holding with shutter speed up to 1200. Appreciate any advice. Alicen

[Anonymous · Accepted solution]

If your subject is further than 3 meters away, setting the lens on 3 meters to infinity will help the lens focus more quickly. If closer than 3 meters, then set it to full so the lens can focus closer than 3 meters. If set it to full and you shoot a subject farther away, it may take a little longer to obtain focus, but should work. Full gives you the full range of focus for the lens, without concern on your subject distance.

The focus limit switch just limits the range of focus distance to enable quicker focusing.

[rs-eos · Accepted solution]

If what you're photographing will always be 3 m (approx 10 ft) away, then set the lens to "3m to infinity".  By restricting the range, that will help achieve focus more quickly.

You'd set it to the full range if you'd end up taking photos where subjects could be at varying distances, to include down to about 1 m (3 ft) which is the minimum focusing distance.

Can you further explain what is not working?  Do you have example images you have taken?   Can you estimate how far away your subjects were?

[ahardy]

thanks again, you all are great. I have a much better understanding. Most my shooting is distant, so will keep on 3 to infinity, but remember to flip it if something is closer (not bears, lol).

[ahardy]

thanks, after reading everyones comments, I understand it much better! you all are great!

[ahardy]

thanks, I learned from your comment that 3 to infinity maybe helpful to avoid a tree branch. Hasn't really been a problem yet, but will keep that in mind. 

[kvbarkley]

As you can see, I learned the hard way:

[wq9nsc]

The focus limiter won't have any effect upon sharpness once the lens is in focus, ONLY on how quickly it may achieve focus.  For wildlife situations like you describe, setting it to limit to 3 meters and beyond will provide faster focus acquisition under SOME conditions but image quality will be the same regardless of the limit switch setting.

150-200 yards is a long distance for a 500mm lens.  At 600 feet, the field of view is going to be around 28 by 42 feet so even a grizzly is going to occupy only a small part of the sensor.

If lighting conditions permit, try stepping the lens one stop down from fully wide open and it might marginally help with image quality but if lighting isn't excellent then the increase in ISO would more than offset any gain in IQ.

What is the ISO for your captures?  As sensor amplifier gain is increased at higher ISO, so is noise and some softening will occur as part of noise reduction.  This becomes much more problematic when heavy cropping is needed due to focal length and distance issues.  This is a case where you want to use the slowest shutter speed possible that avoids blur in order for the ISO to be as low as possible for a standard exposure.

Rodger

[ahardy]

If I'm hand holding my shutter speed is 500-1000, which sometime I need to to get around trees or I can't get out of the car.  Your reply makes great sense to use my tripod (it's manfrotto 055) if possible to lower the shutter speed. Thanks for the reply!

[ahardy]

Also, I realize the distance shot are difficult, just trying to improve them as much as I can. 

[kvbarkley · Accepted solution]

Two points:

Are you hand held?

If one of the allowed focus points has an object closer than the subject - like a branch in front of your wildlife, the camera will focus on that. DPP will tell you what the camera is focused on. I also suggest keeping the focus points in the center.

[ahardy]

yup, Usually use spot focusing, appreciate the reply.