Racing (semi-serious) photography question - polarizer or not ? (focus speed and accuracy)

Being that this is a car-forum, and not a photography forum (...sometimes it's hard to find the right people who are knowledgeable enough about both...), just looking to see if there are any serious amateurs or pros with opinions:

I love my cars, and I've been semi-serious with my cameras for probably about 10 years now....
Current equipment that I take to spectate with (Sahlens Six Hours at the Glen, PWC, Continental, Tudor, Rally America STPR in Wellsboro, PA, local autocross, etc...) is a Canon 6D (about 1 year old) and backup 60D, and 100-400mm IS L (not the new MkII version, I've had this for about 8 years). I have a 70-200 L (non-IS) that I never ever use (because no IS), and a 24-105 L for walkaround and some video nonsense. I also usually shoot with a circular polarizer. Not a super expensive one, but not the cheapest one I can find either. Mine says Hoya CIR-PL on it, for what it's worth (doesn't seem to indicate if it's a specific series, but I'm sure it didn't cost more than $35. I wasn't convinced that I needed the $150 filter).
Anywho. I like the effect that the polarized filter gives me, I can see the driver through the windshield, and sometimes catch some expressions, or a cool iridescent visor.
When I browse through the various car magazines (Sportscar, GRM or something like the official fan-guides from a race), I see many shots that are obviously using a polarizer (where you can see clearly through the windshields, and you can tell by the way the light reflects off of the bodywork), and there are also some where there is no polarizer.
My problem (or perceived problem), is that even in broad daylight, my autofocus hunts around more, and I seem to get less sharp focus consistency.
So what I'm wondering is (an opinion survey I suppose), for anyone that shoots semi-seriously, do you have similar experiences with polarizers messing with your AF, or softening your images ?
Do you have any experience with exactly the equipment I'm using and think maybe I'm just being nit-picky ? (I'm not a pro, but I'm always aspiring to shoot something on that level if I can).
I don't know that I have any specific photo examples. But I'm mostly curious to see what others have to say.
I hear that there are some variances from lens to lens (better and worse copies of a specific model). And while it would be fun (maybe) to dump a pile of money into a newer lens (if it would really make a difference), maybe I'm just trying to combine a difficult set of things (polarization, fast moving targets, semi-pro but not absolutely top-of-the-line equipment), and that I'm just going to have to shoot a lot at each race and do a lot of sorting and cropping later...
(I am not crazy about sorting and editing, I like to get it right straight from the camera if I possibly can).
Okay, thoughts if you have them !!! thanks :D

Light is always your friend and a polarizer reduces it. I'm guessing you're already shooting pretty far into wide open with short shutter speeds, so the only way to get more light is to bump the ISOs, buy a much more expensive lens (crazy f/2.8 territory), or dump the polarizer.

I can't really add more food for thought because your kit and experience are both better than mine!

Stop using AF. Seriously. Plan your shot; it's a racetrack - the cars arrive at very similar spots lap after lap. Pre-focus on that spot, track the car(s), then pull the trigger when they hit your chosen framing.

FWIW, I shoot races on film, so getting it right in the camera is pretty much the only option.

In reply to 02Pilot:

Start working on getting to this point. I will use the pace lap for setup, then shoot the first 4-6 laps in manual mode and shoot the last 2-3 laps in auto, and compare my progress to the AF as a measuring stick. It's harder to do at stage rally, but for Club Races it's the way to go.

Thanks for the suggestions Ky, O2 and Capt, I suppose that breaking down and going to manual focus would be the next logical step.
I seem to do okay at the panning shots, I guess it's more the head-on photos that are tricky.
This is maybe not the best example, since it's two-cameras ago, and it's not polarized, but this is exactly the angle (car coming over a crested turn) that the focusing can be iffy with (granted lighting is not super bright in the forest here either):
David Higgins - STPR 2012

Here is a shot with my current setup. exactly the kind of photo that ends up being a little soft. I don't have a 2.8 zoom currently, and I know that shooting wide-open isn't optimal for sharpness... but I still kind of want the minimum depth of field effect to isolate the car from the background....
probably too many things to try to combine into a single shot, and expect consistent results.
CTMP 2014 - Continental car over crest
Here's a sorta-pretty-okay panning shot:

CTMP 2014 - BMW Z4

The quality is hard to see due to where they are uploaded to (compression and whatnot), but just to give an idea of the exact type of shot I am trying to improve.
picking a static focus point when the cars are coming head on is challenging. But if that's the best way to do it, I can try that out in a few weeks at my next race.

(sorry for links instead of embedded photos, facebook makes it more difficult to hotlink a photo... you may have to click "open in viewer" to see a slightly larger version)

Modern digital cameras do not need polarizing filters like film cameras did. The imaging within the camera controls most of what a PF does already. Take some up sun shots and you see there is not a lot of effect to remove.

They can be used to give the sky a bit more color (depending on how they are turned) but they will block out some light (which also can be useful depending on what you are doing).

The general trend with digital, is to capture as much as you can (e.g. raw files) then process afterwords to get what you want, which is much easier these days with software.

In reply to aircooled:

Well, the main reason I'm hooked on the polarizer is that I can give it a slight twist and see prefectly through front windshields (which can't be done in post-processing), but I can also selectively darken up pavement to highlight tire tracks quite noticeably (that in particular could be done with some manual editing afterward, but I try to avoid post-processing as much as humanly possible if I can).
It also is a quick way to bring out colors of paintwork by removing the glare from the sky. I could adjust the levels and curves afterward to enhance colors, but the only way to remove the glare is to keep the camera from seeing it initially. For me, having the polarizer on, and adjusting it as I shoot (turning it depending on angle of sun and which way I'm facing) saves me many hours adjusting colors and contrast afterward.

In reply to aircooled:

Most filters are pretty redundant when used with modern digitals, but polarizers still serve a useful purpose. And while I recognize the possibilities of post-production editing, and I do use it when necessary, I think there's also a tendency to rely on it too heavily. I, for one, do not like spending hours in front of a computer fixing things that I could have gotten right in the first place. I'd rather work on being a better photographer than a better editor.

100-400mm with a crop sensor camera is a REALLY long (and slow) lens. Then when you add in the polarizer you just aren't getting enough light to the sensor and that is what is throwing off your AF.

Based on the pics you posted, I think it would be perfectly possible to get those same shots with a much shorter lens. Try this - use the polarizer on the 24-105 (105mm on a crop Canon is still the equivalent of 168mm) for one event or even one set of shots. Try to get closer or position yourself somewhere (safely) that the cars come closer to you. See if you like those shots better than the ones you are now taking from farther away with your super-long tele lens.

In reply to SEADave:

I'll try to force myself to spend more time with the 24-105 at my next event. I did use it a little at the stage rally a few weeks ago, and I did crop a lot of photos, but the drivers all seemed to like seeing the photos and there were no complaints, so I guess that's good :D
The 6D that I'm using is actually the bargain-basement entry-level full-frame model in the lineup, but I do have a 60D (APC-C crop) that I can use and compare against too I suppose.
I think you are probably right that the reduction in light is not helping the AF system any when trying to do its thing.
Now, if they could just knock down a few fences or if I could find a way to get closer to the action.....

Have you considered ditching the zooms and getting a faster prime or two? I almost always shoot with primes (to be fair, this is largely due to using rangefinders over SLRs in most cases) and I much prefer the simplicity. You could set up two bodies with a shorter prime on the full-frame and a longer one on the APS-C, giving two options ready for use. I don't know what your preferred focal lengths are, but there are lots of options in EF mount.

lastsnare wrote: In reply to SEADave: I'll try to force myself to spend more time with the 24-105 at my next event. I did use it a little at the stage rally a few weeks ago, and I did crop a lot of photos, but the drivers all seemed to like seeing the photos and there were no complaints, so I guess that's good :D The 6D that I'm using is actually the bargain-basement entry-level full-frame model in the lineup, but I do have a 60D (APC-C crop) that I can use and compare against too I suppose. I think you are probably right that the reduction in light is not helping the AF system any when trying to do its thing. Now, if they could just knock down a few fences or if I could find a way to get closer to the action.....

If you have a full-frame camera, definitely use that. I was in no way suggesting some sort of superiority in crop-frame cameras. I haven't been keeping up with Canon and assumed from the price that the 6d was crop sensor camera.

I was just suggesting that if you could get the same shot from 40 feet using a 100mm lens at f4.0 (or better yet f2.8) you were better off than getting the same shot from 160 feet using a 400 lens at f5.6 (unless you are looking for really shallow depth of field). This is especially true when you then put on a filter which takes away another 1.3 stops - making your 400mm f5.6 effectively f9.0 wide open.

In reply to SEADave:

That's a good option to consider as well. My 100-400 lens is probably mostly in the 300mm range when I'm shooting, although being on the spectator side of the fence at race tracks limits the fence-free angles that I can get, which is mostly why I'm attached to the 400mm capabilities.

O2Pilot, the longest prime I have right now is just the 85mm 1.8 (non-stabilized), but I could look into something like a (stabilized) 200mm prime 2.8 or so, which might not break the bank too badly (I think there is something in that range that is decent that isn't as incredibly expensive as some of the longer lenses).
I know that there are 300mm and 400mm L primes, but I forgot if they are really really expensive, or just pretty expensive.
Having experimented once with a non-stabilized 500mm lens, I think that any of these would be tough to work with if they didn't have the IS.
After chatting a little bit more with a few of my friends that do other types of photography, the consensus is that, what I'm trying to accomplish has several factors working against it, and is one of the hardest things for the camera to do (fast moving subject, coming straight toward you, using autofocus, with a polarizer in the mix).
In my particular case, one of them said that on my camera, of all the AF points, the center one is "cross-point" (better) while none of the others are, so always use the center focus point. And also to look into the AF custom functions that adjust focus sensitivity, refocus-timeout, and a few others)

The cameras I shoot with were old enough to vote and then some before the words "image stabilization" ever appeared in camera-maker ad copy, and I've used them with 200mm and even 300mm lenses successfully, and so did thousands of photographers before me. And that's on film, max of 800 or 1600 ISO. With the ability to dial the sensitivity up to 11 you should have no trouble getting the shutter speed up to the reciprocal of the focal length (rule of thumb for stability, if you're not familiar), so with a 200mm lens you want at least 1/200 on the shutter. Image stabilization is great, don't get me wrong, but it's not necessary in most cases if you pay attention to staying inside the stability envelope on your own.

I suggest you give the 70-200 another chance. I assume yours is an f/4? The newer f/2.8 is spectacular. If I was going to spend an unhealthy amount on money on gear, it'd be at the top of my list. I bet yours is still sharp enough to shoot wide open and get good results. And that zoom range seems to be about perfect on a full frame. As has been stated, the IS is not really as important as you might think. The 6D should allow you to bump the ISO to get the shutter speed up.

As far as the polarizer, I also like the effects it can provide. As suggested, if you get your shots set up ahead of time, with manual focus and filter dialed in, you should be good to go.

In reply to G8MikeGXP:

As you were mentioning the stabilizer not being as important as I think (and I was constructing a reply in my head about why I need it)...it occurred to me that the exact shot I'm trying to get (head-on) really doesn't need the stabilizer at all, if my shutter is fast enough. (and for panning shots, which aren't a problem for me, I could still use my 100-400 IS lens, and get some good motion/wheel blur).
Yes, my 70-200 is the f4 L non-IS (the one that usually goes for $600-700 new, and is supposedly super-duper sharp). I've had it for longer than the 100-400, but it always seemed redundant once I got the 100-400, so I often don't even take it with me, sadly. I am very tempted to at least rent a 70-200 2.8 L lens. As much as I read about them, I suppose the true test will be to actually shoot with it and see what kind of results I can get. While it's a good chunk of $$, maybe it would be worth it (fortunately lenses don't turn to rust like cars do here, so there is always the option to sell it someday if necessary).
So maybe that's what I'll do at The Glen in 2 weeks, where I'll have a few days to really give it a good trial.

I think it's been covered: shoot manual (zone focus) and use 'fast' primes. I'm kind of odd in my SLR experience... when going from 35mm film to digital SLR I still used 35mm film prime lenses and focus manual, because I had tons of the lenses and it would be a shame not to use them. The images will never be as sharp or colorful as a fully digitaly designed system, but I don't care...I enjoy using one of the first Pro level DSLR's ever made with all manual 35mm lenses. If you know about driving on a track and about photography then you know where the shots are going to be on track and manually zone focusing works well. From my experience with DSLR (albeit a 4/3rds sensor one), 100mm to ~250mm fast primes is where you need to be for track photography. But yes, plan your shots in advance and then take them manually focused:

I believe this was taken with the OM Zuiko 135mm F2.8...

This was probably one of the most difficult shots I've done, upclose with a normal 50mm lens on C5R going fast on a 'straight away' requiring a super fast pan and precise timing at night.

My biggest mistake in life was selling the extremely rare and legendary OM Zuiko 250mm F2...the absolute best 35mm SLR lens Olympus ever made. I miss that lens... Image taken with it completely untouched, straight from my camera setup (which doesn't do the lens full justice):

From an airshow...

I think the 180mm F2 Zuiko would be a better prime for shooting racing compared to the 250mm as it would allow for a little more flexible framing with a 4/3rds system SLR. If I had the finances I would TRY to find one.

Polarizers are your friend–most of what I shoot for the magazine that's outside is shot through a CPL. Why? They make colors pop, they help you see through glass, and they make paint look deeper.

Now, they aren't good when they make weird patterns in glass (assuming you care about that, for many shots it isn't a big deal), or when they darken the image too much. Though if you're shooting in full sun, as you usually are at a race track, I wouldn't worry about that.

As far as focusing when shooting on-track stuff, pick one point to focus on, focus on it, then wait for the car to arrive there. Oh, and don't hold the shutter down for 19 shots hoping you get the right one. Take one or two, and make sure you're patient enough to wait for that first shot to be /the/ photo with the car in the frame the way you want it to be.

In reply to Tom Suddard:

Thanks for your thoughts Tom and Vracer. Great photos.
I do completely agree about the polarizer Tom. I guess when I shoot without one, everything just looks kind of dull by comparison. Enough to where I'll take the colors over 100% perfect sharpness if I have to pick one.
I also agree about holding down the button. Going through 15 of nearly the same photo (multiplied by however many cars pass by at a viewing spot) is just agonizing after not very long ([inner dialogue]: "...seriously Nate, why did you take 200 photos of the same car at the same corner....again...I thought we learned this lesson last summer....")

Here's one photo from last year at CTMP (Mosport). I am not sure that I can embed the photo, these URLs are getting tricky now, but the link should work:

Ferrari passing pits - CTMP 2014

the link should allow some zooming with the mouse-wheel. It's a good photo, but I just think it could be a tiny bit better with the sharpness.

another:
Porsche #911 passing pits

So again, not bad photos. I just like to keep making things better if I can

Just a question, and I ask in all seriousness: why the obsession with sharpness? Are you printing massive wall-size murals, or cropping extensively before printing? There are many, many things that make a good photograph, and sharpness is well down the list.

In reply to 02Pilot:

Well, I'm not sure why I'm so obsessed with the sharpness aspect so much. I guess in one sense, it just bugs me a tiny bit when I view it at 100%, and it looks like it might not be as sharp as it could (without sharpening it in software afterward). And I just want it to be better. It could be that I've taken so many photos from the places I'm able to get access to, that I am searching for something to keep moving forward with. I probably get bored. Maybe photography isn't something that I just completely enjoy enough, in and of itself, that I can just shoot pictures, post them someplace, and be happy with what I get.
That characteristic extends to other interests I have also, so it's probably just a personality quirk/feature of mine. I get excited about something, do it a lot, get sorta okay at it, hit a plateau or a rut, and try to find some direction that I want to keep pushing in. Trying to make something about it new again, or different, or fresh. Creative rut most likely
Actually, I suppose that I would somewhat be interested in being able to crop down when my zoom doesn't reach far enough, to catch sort of "extreme closeups" of action or drama.... flame shooting out of a side exhaust, heat distorting the air that the car behind is being seen through (but as sharp as possible).
Sometimes I can catch little things like that, but by accident without being zoomed in on it. And sometimes it's just really difficult to track such a small part of a car, at those speeds, even if I was close enough (and lucky enough) to zoom in and catch a moment like that.
So if it's sharp enough, I can crop way down to something like this.

here is kind of a "moment" (flames from an Pro Mazda/ Indy Lites, I think, exhaust, maybe those are the same series :P ), I think this was cropped a lot, also a few cameras ago, so not fantastic, but with the 100-400 I'm sure:

Pro Mazda or Indy Lite exhaust flame

There is also some 'gear acquisition syndrome' (I've done this with guitars, other instruments, etc...).
The old joke that "the only way to truly improve as a drummer, is to get a bigger drumset." (I poke fun because of my prog-rock interests in the past, and complicated musical background :P ).
It does seem to hit diminishing returns eventually though. Like at this point.
My first camera was a point and shoot digital when I worked at Circuit City in college. It was easier then to freshen things up by getting new equipment, trying a new kind of filter, frame the photo differently, etc.... Now, getting up there in $$$ investments, go up a level with any part of my system is expensive. So that's kind of a bummer. But that's how it goes sometimes. Not to get discouraged, but to press onward if I can, regardless. Artistic rut solved by buying more stuff :P
And yes, I'm also reading the other thread about being burned out on the car hobby. haha.

As an amateur photographer but with IMSA credentials (see you at The Glen?) - I have never used a polarizing addition. My concern is because I use the Internet to share photos, I have far fewer concerns about some of the quality than do the professionals and magazine (print) photographers. Examples of my fun; https://www.facebook.com/sput.dodge/photos_albums and www.scunleashed.com

Also, I use all these options discussed during a race weekend - slow shutter speeds, fast shutter speeds, auto-focus, manual focus, panning (lots of panning), all of it. Some people will say race time isn't the time to experiment and try new things. I disagree, I'm always trying to get the same view photographed a little differently.

Hey, I know all about Gear Acquisition Syndrome. I know all about needing something that will most assuredly turn me into a much better photographer (not). It affects us all in one way or another, with cars or cameras or in whatever other equipment-requiring activity you care to mention.

I can only speak based on my experience, and this may sound ridiculous, but it's worked for me far better than GAS: regress. Instead of buying and using more stuff, use less. Better yet, purposely use inferior gear, and less of it. One body, one lens. Buy a cheap EF mount film-era prime and go to work. It will be more work, but I bet you get more out of the experience.

With a bit of distance you can set the focus to infinity on manual and not have to worry about autofocus speeds.

I don't know what lenses from the Canon library to look for. A ~50mm with an F-stop somewhere faster than 2.0 would probably be nice and I think there's a lot of those out there. Maybe something again near 100mm?

I've never really shot with a polarizer much, but one thing I really need to get is some neutral density filters... because bright midday sucks for photos when you have to close down aperture and make the cars look like the are parked on track...LOL But that's the nice thing about 24 hour endurance racing (and not being a pro): you don't need to shoot during the boring midday...and can instead scout and pick out where you will be shooting once it's the right time to shoot... LOL

And one thing I did at the 50th anniversary Daytona 24hr race was take notes of what lenses worked best for how I like to shoot. Here's what I wrote:

24hrs Daytona corner notes [A.] Infield Carousel 1 entry - 50mm & 135mm(best) [B.] infield Carousel 1 exit - 135mm & 180mm [C.] Infield Carousel 1 exit to before Gator - 50mm, 135mm, & 180mm [D.] Gator - 135mm [E.] Infield Carousel 2 exit - 135mm & 180mm [F.] End of straight after infield Carousel 2 - 50mm, 135mm, 180mm [G.] Banking after infield exit - 135mm, 180mm, 300mm

My takeaway from this is 135mm would work quite well if I just wanted to use one lens for the Daytona infield...and the OM Zuiko 130mm F2.8 is not that much bigger than the Zuiko 50mm F1.8... so a very small lens.