soft focus problems with 70-200 2.8 lens

[anguslincoln]

I am wondering if I am expecting too much image clarity and focus from my 70-200 mm 2.8 lens. I have been shooting a lot of birds with it from as close as 2 meters out to 50 meters.I have some fantastic results, but focusing seems to be inconsistant . I use it hand held mostly with good support at fairly high shutter speed when the natural light supports it. I was hoping to have less soft focus at the longer distances of 20+ meters. Is this lense capable of sharp focus at those distances if propper exposures are used ?

[ebiggs1]

What camera?  Which 70-200mm?

That asked, are you using center point focus?  

The EF 70-200mm f2.8 L IS II is very sharp (at least mine is).  As sharp as can be had with a lens like this.  As a matter of fact it is the best lens made.

[cale_kat]

Your ability to hold a camera steady might be insufficient at 20 meters. Use a tripod, properly secured for stability, and report back. You haven't done enough testing to have drawn reasonable conclusions about the lens as of yet.

Just my 2 cents.

[anguslincoln]

I agree and thanks for the reply....being new to this forum, I realize now, I could have had found a wealth of knowledge from reading about similar issues that others have already diagnosed. There is much to learn from all you nice people here ! I am in Brasil right now and I only brought my monopod. As soon as I can get my hands on a tripod, I will do some further testing. Affordable equipment is not so easy to come by !

     Am I correct in thinking that by making my aperture smaller and keeping the shutter speed above 600 or so will improve sharpness, even though I will need a higher iso setting ? Up until now, I have always tried to keep the iso as low as possible to achieve the best clarity, but after reading answers to problems here on the forum, I see that this may not be the best theory.

[cale_kat]

You know the mechanics well enough, IMHO, but 1/600 might not be fast enough for your purposes. My camera will shoot 1/8000 of a second! Absolutely unheard of when I first took up photography.

[anguslincoln]

Wow ! I haven't tried anything that fast ! My typical subjects are birds and and critters you might come across walking through the forests here ! I keep two 7D's with me mounted with the 70-200 and the 100mm macro. I am really wishing I had the tripod I bought for the trip here, but space was limited. One of the challenges I am dealing with is constantly changing light ! The forest has overall darkness with places of intense brightness at times ! Unfortunately, the birds seem to prefer the shady parts. But every once in a while, I get lucky !

[cale_kat]

Sounds like great fun when you get your shot. A little reading for when you're bored...http://www.lensrentals.com/blog/2009/08/how-to-get-sharp-telephoto-images

Good luck.

[ebiggs1]

Big telephotos have a learning curve. The bigger tele, the longer that learning curve will be.  And 1/8000 is not the answer.  Usually?  Mirror slap is violent at that speed by necessity.  It by itself can add vibraton.

Also the IS is varibile, one stop is pretty good, two stops isn't as good and three stops not as good as two, and so on.

Switch IS off on a monopod or tripod.

The key here is to try several different things and shoot a lot. Keep track of what works and only read what you need to to get the basic knowledge.  You really can't leanr photography from a book.  You must shoot and a lot as said.

There are a lot of keyboard-photographers, don't become one of them.

[RobertTheFat]

---

@ebiggs1 wrote:

Big telephotos have a learning curve. The bigger tele, the longer that learning curve will be.  And 1/8000 is not the answer.  Usually?  Mirror slap is violent at that speed by necessity.  It by itself can add vibraton.

I'm no expert on shutter mechanisms, but the assertion that mirror slap is in any way related to shutter speed surprises me to the point of disbelief. The shutter curtain shouldn't start to move until the mirror is out of the way, and how long that takes should be a constant for any given camera. Manufacturers try to get the mirror out of the way as quickly as possible to minimize lag, but lag is undesirable at any shutter speed.

Also the IS is varibile, one stop is pretty good, two stops isn't as good and three stops not as good as two, and so on.

Switch IS off on a monopod or tripod.

On a tripod, yes - although some lenses are apparently smart enough to recognize when shake is not an issue. But on a monopod? That's far from obvious. A monopod, used correctly, should greatly reduce shake, but it can't eliminate it altogether.

The key here is to try several different things and shoot a lot. Keep track of what works and only read what you need to to get the basic knowledge.  You really can't leanr photography from a book.  You must shoot and a lot as said.

There are a lot of keyboard-photographers, don't become one of them.

That I can agree with!

---

[ebiggs1]

I am going to break a rule to not argue a point wiht other forum users but you seem to be a pretty reasonable guy.

Cameras that can generate the insanely high shutter speed of 1/8000 have by design mirrors that move very much faster than older bodies that could not reach that speed.  There is no point in being super fast for a 1/1000 or even 1/2000 shutter.

You don't want a camera that opens it's mirror and waits for a fraction of a second for the mirror to stop rebounding when you want or need 1/8000 sec.  A mirror can take as long a 1/30 to stop rebounding.  The camera is shaking all this time.

Is 1/8000 better than 1/80? Absolutely but it in itself is not the answer.  The answer has several aspects, not shutter speed alone.

As in all electronics IS is varible.  It will works better at a 1-stop disadvantage than it will at a 4-stop.  That is just the way it is.

When the manufactuer says the lens has a 4-stop IS feature, they are really stretching the spec.  Does it work at 4-stops, yeah, but is it as good as at 1-stop. No, it is not.

The IS function should be turned off on a tripod and even a monopod.  The IS can actually work against you as most lenses have no idea wheter they ae being hand held or not.  Now if you don't want to turn yours off, please, feel free to leave it on and shoot away.