70-200 F4 sharper without UV?

[foley71]

OK, maybe this is just my imagination ... or user error.

I got the 70-200 F4 at Dell not too long ago (at a great price), and I picked a Hoya UV filter to go with it. I got the filter on ebay, and it was cheap.

However, I've had somewhat of a tough time with the lens, particularly when I'm shooting action. It seems like it wants to focus everywhere except the action. So if I'm in the backyard with the dog and he's chasing a football around, the grass or the shed is often in focus, but not Murphy. I live in upstate NY, where we're still waiting for consistent sun, so a lot of the shooting has been done at 4.0 and 1600 ISO. Still, like I said, things in the images will be in focus, just not the action. In fact, I've watched the red dots that show where the camera's focusing (please excuse the very un-technical langauge here), and it seems to like focusing in stationary objects.

I also have an 100mm F2 and a 50mm F1.8, and perhaps they've spoiled me. They have Canon UV filters on them, but typically their focus is pretty accurate.

Interestingly enough, it was bright out today so I took the 70-200 out. Out of curiousity, I took the filter off and shot without it. I'd say 75% of the shots were focused on the action. Now, thanks to the sun, I was able to shoot everywhere from F4 to F9 ... So is it me, the Ffactor or the filter?

Another thought: I know that the DRebel features al servo. I believe it's automatic in the Av mode. Am I right about that? I don't have to activate it in any way, do I?

Anyhow, sorry for rambling. I'd guess that this is largely my inexperience. I've only been using the DRebel since January, and I just recently upgraded my lenses. When the L lens is on, it is REALLY on. I just want to figure out how to get it that way more often. And I figured someone on here might have experienced something similar.

Thanks for any help.

Jeff

[HJMinard]

Another thought: I know that the DRebel features al servo. I believe it's automatic in the Av mode. Am I right about that? I don't have to activate it in any way, do I?


The DRebel uses "AI Focus" in most modes, including Av: it starts out working in "One-Shot" autofocus, but if it senses movement toward or away from the camera it automatically switches to AI Servo. It doesn't really work that well, in my opinion. The only way to put the DRebel into full time AI Servo is to utilize the "Sports" mode.

[foley71]

Thanks, Jay.

I'm a ways off from upgrading the camera -- I love the DRebel and still have a ton to learn about it (I actually start a digital photography class next week), but out of curiousity, what Canon cameras are better with AF?

Also, does it make sense that one lens (i.e., 100mm F2) would AF better on moving subjects than the 70-200 F4? I guess I wouldn't be surprised if it's simply user error or me still needing to really learn how to use the lens.

For any other sports shooters out there who are using a DRebel, what methods do you use to get the best focus? I've heard that some people simply put the AF in the center and try to keep the action there ... Any other ideas?

Jeff
www.foleypics.smugmug.com (http://www.foleypics.smugmug.com)

[tim]

Which Rebel do you have? The 300D doesn't have AI servo, I think the XT does.

If you're going to use a filter use a good one, i've never heard of them causing focusing problems but i've never used cheap ones myself either.

[HJMinard]

I love the DRebel and still have a ton to learn about it (I actually start a digital photography class next week), but out of curiousity, what Canon cameras are better with AF?

Well, almost any Canon DSLR (20D on up to the 1 series) would be an improvement, but the DRebel's autofocus isn't that bad ... it's just the lack of user selectable AI Servo (other than Sports mode) that is limiting. With practice, the DRebel can be used effectively for action photography.

Also, does it make sense that one lens (i.e., 100mm F2) would AF better on moving subjects than the 70-200 F4? I guess I wouldn't be surprised if it's simply user error or me still needing to really learn how to use the lens.

Sure, it's possible ... some lenses definitely autofocus faster and more accurately than others. I haven't used the 100/f2 ... but I'd say my 70-200/4L handles action quite well.

[CyberDyneSystems]

Interestingly enough, it was bright out today so I took the 70-200 out. Out of curiousity, I took the filter off and shot without it. I'd say 75% of the shots were focused on the action. Now, thanks to the sun, I was able to shoot everywhere from F4 to F9 ... So is it me, the Ffactor or the filter? ....


Thanks for any help.

Jeff

Jeff,

It certianly could be the filter,. you would not be the first one to have such trouble,.
Sometimes certain combinations will mess upo the AF accuracy.

I went through this about two years ago with a particualr Hoya filter on a particular lens. The same filter on another lens offered no problems,. in fact I still use that filter now,. and the lens on it's own,. or with a different brand filter had no issues either.

It does happen.

[foley71]

Thanks for the replies. I will simply keep shooting and see what happens. As I've said, I'm sure that part of it is my inexperience. I'll get there, though.

I'm definitely going to try a better UV lens. (Any suggestions?)

And some day, when I've mastered the DRebel, I'm sure I'll move up the camera ladder. For now, it is all the camera I need (and more). I love it.

Thanks again.

Jeff
www.foleypics.smugmug.com (http://www.foleypics.smugmug.com)

[mguna]

Hi there,

Have the 70-200/f4 and bought the Hoya HMC UV-guard filter. Understood this means a high multi coated filter. Have not seen any image deterioration.
You state that your filter is also from Hoya...what type is it?

Further info in the filter can be seen at...

www.photofilter.com/hoya.htm (http://www.photofilter.com/hoya.htm)

Regards
GunaM

[foley71]

I think it is the most basic of Hoya UV filters. Seriously, it simply says Hoya UV 67.0. There is no HMC or anything like that.

I hate to admit this, but I won it for $5.50 on ebay. I know cheap is not the way to go, but after spending $600 on the lens, I was obviously trying to save a few pennies. Looks like the smart thing to do is to spring for a better filter.

And it's funny -- it's not so much that the images are bad as it is that they are not in focus in the right places. Like I said before, with the filter on, the AF is everywhere but on the action. Without the filter, though, it was much more accurate. However, that's not a great test because I was also able to use a smaller appeture and ISO yesterday, when I took the filter off.

So I'll keep playing around and, if I need to, order a better Hoya UV.

Jeff
www.foleypics.smugmug.com (http://www.foleypics.smugmug.com)

[Jackal]

I'm looking into buying this lense and of course I'd like to have a UV filter for some protection if I'm ever at the beach shooting an airshow or friend's surfing. Most of the time there's a heavy wind coming from the ocean and it blows sand, salt, and crap onto the lens (and my glasses which is annoying). I couldn't imagine wiping the front of such an expensive lens with all that sand on there and cause a bunch of scratches.

Is this UV filter any good?

67mm UV Haze (HMC) Multi-Coated Glass Filter - Ultra Thin

[mguna]

IMO, you should discard the filter and get a new one. The filter basic function should be to protect the expensive lens and there should be no effect on the picture.
I normally get my stuff at the store called John 3:16 (S'pore)....The staff there are pretty good and are knowledgeable. You should get a good filter as you do not want the front lens to get scratches or smudges and once it on, you would not want to remove it.

With regards to the UV Haze filter, not sure as I do not have it but believe that HMC filters are correct as they are multi-coated. The ultra thin should be for special lenses where inclusion of filters might scratch or might be too close to the front lens.

regards
GunaM

[KrisForsberg]

Drop the filter! They only make pictures softer and sometimes they make strange ghosts on pictures under certain lighting conditions...!
Use the shade and leave the filter home unless you shoot in sandy (mentioned) or salty conditions. When it comes to protection from impact, a filter can make matters worse - pieces of broken glass and coating don't mix! The shade protects better than any filter.
Better pictures and (possibly) better focus is what yo get without it.
As for your focusproblems I wouldn't blame that on the UV-filter... Capturing objects in motion needs a lot of practice - I'd say it's the photographer (sorry) and not the camera. However, the f/4L needs a good amount of light for the AI servo to function properly and you mentioned that there was alot more light. I'd say that this is the only cause for the difference.

Kris

[Medic1]

I thought I had already replied to this thread but I guess not..lol.

I too found my 70-200 f4L had some quality problems when using a Hoya UV filter. I took the filter off when taking the same image only minutes apart (so same light etc.) and found that the image was much sharper with the filter off. I haven't had it back on the lens since.

[Jackal]

Medic, was that the most basic Hoya filter?

How good would this filter be on the 70-200?

http://www.bhphotovideo.com/bnh/controller/home?O=WishList.jsp&A=details&Q=&sku=23733&is=REG

Anyone have any experience with this combo?

[tim]

Jackal - multicoated is good, that looks like a mid range hoya to me, should be ok. I ordered a good B+W for my 70-200L, which i'll compare with my Hoya Pro-1 when it arrives.

[Jackal]

Thanks.

How about this one?

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=94132&is=REG

It's like $10 more expensive. Would it be worth it?

[tim]

Probably - if you're going to bother with a filter get a good one, no point putting crap glass in front of good glass.

[Sean-Mcr]

On the subject of filters for protection, i found the below article interesting just one view of course but still an interesting read

http://www.luminous-landscape.com/columns/sm-feb-05.shtml

[Tom W]

Here's a little more on filters, cheap filters, and flare:

http://photography-on-the.net/forum/showthread.php?t=56907

About halfway down, I did a little comparison.

[Medic1]

Medic, was that the most basic Hoya filter?

How good would this filter be on the 70-200?

http://www.bhphotovideo.com/bnh/controller/home?O=WishList.jsp&A=details&Q=&sku=23733&is=REG

Anyone have any experience with this combo?

No it was not, that was a Hoya HMC Super Mulitcoated UV filter

[WepWaWep]

I too am using the digital Rebel and a L series Tele, the 100-400. As for the focus. Having shot skeet, I have adapted the same techniques of getting a bead on the subject. Practice setting up the AF point, I will use either dead center or the right or left points and work on getting a lock on the most important part of the subject, I prefer the eyes. Swing the lens with a steady motion matching the subject. I shoot a lot of birds, ducks can come in at very high speeds.

I have also suspected that my filter has been causing some softness to my images. Next shoot, I'll be taking it off.

And last, I shoot in RAW only and set the camera up myself. It depends on conditions, but I'l either opt for shutter priority or aperture priority with full manual if the same shot is going to repeated under the same conditions. Why bring home a bunch of Jpegs that have limited post processing options home?

[drisley]

I had the same experience when I first bought my DRebel and the 70-200/4L.
The reason was indeed the lack of AI Servo mode.
I later installed the Wasia firmware that allows a Servo mode and it helped alot.

[ShadowFlyP]

Someone mentioned the "Ultra Thin" filter somewhere above. Be careful with those because the Thin filters often do not have front threads. Without front threads, you usually can't use your lens cap!

[montreal]

So if I'm in the backyard with the dog and he's chasing a football around, the grass or the shed is often in focus, but not Murphy.

Sounds like you're a victim of Murphy's law...