Calculating f/stop to decide on lens

[winn]

I took some pictures at a H.S basketball game (including the cheerleadering

stunts) with the Canon 17-55 f/3.5-5.6 kit lens and the Canon 70-300 f/4-5.6 IS

USM lens. Of course these lenses were too slow and a large portion of the

pictures did not turn out. In reading through the posts in this forum, the 70-

200 f/2.8 seems to be acceptable for indoor basketball games. However, when I

estimate the f/stop needed from these photos I took with the slow lenses to

obtain at least 1/250s and 800 ISO (the 1600 ISO seems too noisey), it comes

out to be 2.0. Am I on the right track? Is it correct to calculate the f/stop

for one type of lens based on the performance of a different type of len? I

would love to get the 70-200 IS USM; however the data is pushing me to a series

of prime lenses including Canon's 135 f/2 USM and the 85 f/1.8 USM lenses.

Thanks...

[JDMvW]

If you're not willing to pump up the ISO above 800, then you will need much faster lenses. For faster lenses, you're going to get only f/2.8 and a 100mm less telephoto and spend a heck of a lot more money.

 

For those of us who grew up with the grainy (read "noisy" in digital terms) high-speed films, 3200 on a modern dSLR (like the 20D-40D) looks pretty good. I've used the older 75-300 IS lens, which is much more primitive than the one you used and gotten good results (IMHO) indoor at the zoo- probably darker than your basketball game.

[bueh]

<blockquote><i>Is it correct to calculate the f/stop for one type of lens based on the performance of a different type of len?</i></blockquote><p>

Yes, it is standardized. There may be a little additional light loss inside long zoom lenses, but this probably does not negate your result.

 

<br> 

<blockquote><i>the data is pushing me to a series of prime lenses including Canon's 135 f/2 USM and the 85 f/1.8 USM lenses

</i></blockquote><p>

Don't forget the EF 100mm f/2 USM prime!

[winn]

I would be willing to go to ISO 1600, which is the maximum for my 400D camera, but according the results of the pictures I took, that would have me at the "ragged edge" at f/2.8.

[William Michael]

>>> Is it correct to calculate the f/stop for one type of lens based on the performance of a different type of lens <<<

 

 

As Bueh wrote: Yes.

 

 

It is also correct to validate what FL (Focal Length) you will need.

 

 

I.E., from the pictures taken with the kit lens and the 70 to 300, was the 135 to 300 FL range used much?

 

 

You should investigate this issue, because, Camera Viewpoint is important to determine the FL used for all sport, and more so for basket ball where the CV might be quite close to the action, (sideline or basket) and the court size is relatively small (compared to football for example).

 

 

So you might find that a 70 to 200F2.8L is in fact too long for basketball, especially on an APS-C body.

 

 

I have found, for basketball with freedom to move courtside / near the basket, a 50, 85 and 135mm prime most useful on 135format (aka Full Frame) the APS-C equivalents would be 35, 50 and 85mm.

 

 

From the stands (depending how early you are to secure the front row and the seating layout) a 100mm and 135 might be long enough.

 

 

If one is really keen to follow School Sport, often it is more practical to invest in another (digital) body and two primes, than a zoom: For example 2 x 400D`s and 100F2 and a 50F1.8MkII is a powerful, and cost effective BBall kit.

 

 

I mention these points for consideration, because whilst the 70 to 200F2.8L is a marvellous lens and every home should have one, it might not be the best suited for BBall.

 

 

In regard to ISO, I think that for School Basket Ball your slowest ISO will be 1600, and that is just life: but your stadia might be brighter than mine (read full Telecast Lighting Banks), but I note all School Gyms I have shot, are usually pretty dim.

 

 

And on another point, I would want to be shooting 1/320 minimum for rebounds and jump shots, and perhaps 1/400 for fast court travel and passes.

 

 

BTW the (varying) additional light loss inside different lenses is referenced by the `T stops` of the lens: the T stops (as opposed to the F stops) are usually only mentioned in cine work, but all lenses having glass elements have (different) light losses.

 

 

As Bueh mentioned, insignificant for practical comparisons, but useful to get the extra half mark in the theory exam!

 

 

WW

[zigzag]

All of the above is very true and getting the best capture is never going to be questioned as the best strategy - but if you are considering pushing ISO to 'get the shot' with whatever lens you have then you do have some recovery options to consider that may still get you 'acceptable' results once you have given yourself a better chance with higher shutter speed:<br><br>

1. Shoot RAW which can tolerate underexposure a little better and then deliberately underexpose by 1/3 stop - this is a fallback strategy as digital sensors are non linear and degradation happens quicker than you may expect<br>

2. Get Noise Ninja to help reduce the noise<br>

3. If you have Photoshop then take a look in particular at the Blue channel which is where a lot of noise is often found for underexposed photos - a subtle blur on just this channel can sometimes help.<br><br>

[winn]

Thanks for all of the responses. I was also reviewing the Focal Lengths of the shots I took. (If I was smart, I would have set my FL to match only the series of lenses I was considering.) William, your courtside experience is a big help. Glen, I'll have to experiment with your options. I've decided to start with the 50mmF1.8 and the 85F2.0 and add lenses from there. It is a tough choice between the 100mm and 85 mm. (I still want the 70-200F2.8 IS!)

[petemillis]

Brian, I've taken loads of photos that at first sight are well underexposed, but I always shoot RAW and almost always I get good photographs once I increase the exposure in Canon DPP and correct white balance.