Aperture ? - 70-200 f4 non-is

[mp2997]

Why would I shoot at any other aperature than F4 when shooting baseball or sports in general. I don't need a wider dof. The reason I ask is that I have read comments about some lenses being soft wide open but I don't understand this. Would it not be sharper wide open? What am I missing?

New to XSI and 70-200 F4 and enjoying them both. Great forum. I have really learned a lot lurking. Thx!

[dmwierz]

This is a fairly complicated topic, but I'll tell you what I know and since that's not much, it's gonna be pretty basic.

All lenses are sharper when stopped down a little from wide open. This is a result of the Physics involved in making a lens. At large apertures, something called spherical aberration reduces sharpness and at smaller apertures diffraction reduces image quality. You want to find the "sweet spot" where aberration and diffraction are more or less balanced out in their impact on image quality and this is normally somewhere between f/4.0 and f/11.

This sweet spot generally is a number of stops above a lens' largest aperture which is one the many reasons why large aperture fast prime lenses are desirable - their sweet spot occurs at a larger aperture thereby allowing you to shoot in lower light and gain the benefits of smaller depths of field while still being at optimal image quality.

I'm sure people on this board who are better versed in this topic than I am will weight in (or you can go to another forum on POTN and do a search).

Hope this helps.

[davethejnz]

Originally Posted by dmwierz

This is a fairly complicated topic, but I'll tell you what I know and since that's not much, it's gonna be pretty basic.

Dennis you are too humble. I trawl this sight often, looking for your words of wisdom and and advice.

Thanks for all you give

[Roy Mathers]

Dennis, I agree with what you say, but does it apply as much to high quality lenses like the 70-200 f/4 IS? What I mean is that I believe the difference between full aperture on this lens and, say, f/5.6, is nowhere near as marked as it is on cheaper lenses.

[dmwierz]

Originally Posted by Roy Mathers

Dennis, I agree with what you say, but does it apply as much to high quality lenses like the 70-200 f/4 IS? What I mean is that I believe the difference between full aperture on this lens and, say, f/5.6, is nowhere near as marked as it is on cheaper lenses.

Roy,

As I understand it, high quality glass often has a wider sweet spot, one that starts at a larger aperture and extends more f-stops (than a lesser quality lens) until IQ diminishes.

[Roy Mathers]

That's really what I meant Dennis, expressed in a different way.

[mp2997]

Thanks for the replies. I am pleased with the IQ I get at F4...just trying to understand the comments I have read on other threads and make sure I am not missing an opportunity to get sharper images. I will experiment a little at 5.6 in good light and see what happens. Thanks again.

[Bkolowski111]

In my own experience, and from drawing on the experience of others, it is often your best bet to shoot your lens wide open when shooting sports. I often shoot my 80-200 at 2.8 even on sunny days. That helps me to get the fastest shutter speed possible and to get subject isolation. Occasionally I will stop down as low as f/4. My lens is pretty sharp at 2.8, but becomes razor sharp at f/4.

You will have to experiment with your lens to find out where its sweetspot is. You will probably have to shoot at f/4 in most sport shooting situations in order to get a fast enough shutter speed.

[dmwierz]

Originally Posted by Bkolowski111

In my own experience, and from drawing on the experience of others, it is often your best bet to shoot your lens wide open when shooting sports. I often shoot my 80-200 at 2.8 even on sunny days. That helps me to get the fastest shutter speed possible and to get subject isolation. Occasionally I will stop down as low as f/4. My lens is pretty sharp at 2.8, but becomes razor sharp at f/4.

You will have to experiment with your lens to find out where its sweetspot is. You will probably have to shoot at f/4 in most sport shooting situations in order to get a fast enough shutter speed.

Brad,
I don't think that's what the OP was asking, plus I don't necessarily agree sports should be always shot wide open. Yes, when you need to pull the subject off a background or in amongst a lot of other things, a large aperture is critical. However, when you have a lot of air behind the subject, like is seen when shooting down the length of a football field or soccer pitch, or across a Major League baseball diamond or even down a basketball court or hockey rink, you can frequently stop down a little, get the benefit of sharper images, a slightly increased depth of field (important for sports like basketball and hockey where players are grouped together with many of them involved in the peak action of the play) and get plenty of subject isolation.

[jptsr1]

Originally Posted by mp2997

Why would I shoot at any other aperature than F4 when shooting baseball or sports in general. I don't need a wider dof. The reason I ask is that I have read comments about some lenses being soft wide open but I don't understand this. Would it not be sharper wide open? What am I missing?

New to XSI and 70-200 F4 and enjoying them both. Great forum. I have really learned a lot lurking. Thx!

of the lenses i have my 70-200 4l shows the least benefit from being stopped down. Only when i am pixel peeping and in the most extreme situations is there a discernable difference (to me). if your getting good shots shooting wide open most of the time and dof is not an issue for you then i see no reason to change your habits.

J.

[Bkolowski111]

Originally Posted by Bkolowski111

In my own experience, and from drawing on the experience of others, it is often your best bet to shoot your lens wide open when shooting sports. I often shoot my 80-200 at 2.8 even on sunny days. That helps me to get the fastest shutter speed possible and to get subject isolation. Occasionally I will stop down as low as f/4. My lens is pretty sharp at 2.8, but becomes razor sharp at f/4.

You will have to experiment with your lens to find out where its sweetspot is. You will probably have to shoot at f/4 in most sport shooting situations in order to get a fast enough shutter speed.

Originally Posted by dmwierz

Brad,
I don't think that's what the OP was asking, plus I don't necessarily agree sports should be always shot wide open. Yes, when you need to pull the subject off a background or in amongst a lot of other things, a large aperture is critical. However, when you have a lot of air behind the subject, like is seen when shooting down the length of a football field or soccer pitch, or across a Major League baseball diamond or even down a basketball court or hockey rink, you can frequently stop down a little, get the benefit of sharper images, a slightly increased depth of field (important for sports like basketball and hockey where players are grouped together with many of them involved in the peak action of the play) and get plenty of subject isolation.

Notice I didn't say it is ALWAYS best to shoot wide open. In my experience I usually don't find it necessary to stop down (when shooting sports). Sometimes I do, but it is not essential. so basically the OP was asking if it is a good idea to stop down, and I am saying it is not essential IMO. If there is plenty of light then its probably a good idea to stop down a bit, but if there is not enough light then its not a big deal if you shoot wide open. Your pictures may be a little less sharp, but you will usually only notice if you are pixel peeping.

Hope that better explains what I was trying to say.

Brad

[[Hyuni]]

I'll attempt to make it a little easier to understand

If you look at a magnifying glass, we tend to look at the center of the glass to see the image, correct? The reason we do that is because the center is the least distorted part of the lens. Once you venture away from the center, the images get more distorted the farther you go away from the center.

Also, adjusting the lens by 'stopping down' or making the hole smaller makes the image sharper. Imagine that you're reading small print. You noticed that you start squinting your eyes to read better. That's exactly what you're doing by adjusting your aperture.

Did that make a bit more sense?

[matonanjin]

You've received great answers on this I am sure they have helped. I do 97.3% of my outdoor shooting with the 70-200 F/4. One of the advantages to this lens is that it is so incredibly sharp wide open.

As you said you don't want a wider DOF and generally want the background blurred to isolate the subject. However, I will occasionally stop down just a hair to get just a slightly deeper DOF. The reason for this is to provide a little bit of latitude on AF errors. This lens is also very fast focusing. But with really fast moving subjects I may just give myself that margin of error. I'm not talking F11 or 16. I'm talking 5.6 at most. And this is only if I have plenty of light and don't have to sacrifice any shutter speed.

[mp2997]

Thanks to all. Last weekend was not ideal (weather wise) so I had to stay nearly wide open to keep my SS 1000+. It is going to be a great day to take pictures tomorrow so I plan to experiment some. I do like the idea of having a little more room for error in focusing with a slightly larger dof.