On Jul 17, 2012, at 4:07 PM, Jack Davis wrote: > That second car is needle sharp. Perhaps partially due to lens compression, > the distance between the two cars is probably greater than might be assumed. > I'm saying that it's likely the focus was smack on the second car.
Note that the ground in front of the 308 is sharply in focus. Also note that the blur on the car is all left to right, and that the car is at the bottom of the hill, very close to the turn down point, the angle of the driver's left hand shows that he could be turning, and the angle of his helmet looks like he might be correcting for the turn. I suspect that since the passenger doesn't have a steering wheel to hold on to, fictional forces are pushing him to the left side of the car, hence the angle of his whole body. At 30mph, he would be doing about 50FPS, or about 4 inches in 1/160Sec (shutter speed). If you look at the car in back, there is actually a bit of longitudinal blur: http://www.flickr.com/photos/bruce_m_walker/7587145124/sizes/h/ I don't think that Bruce blew his focus, he just blew his shutter speed. He was only using ISO 200, probably should have used ISO400 and f/8.0. At least that's my guess, I don't photograph them, I just drive them. I'm interested in what John and Doug have to say. They know a lot more than me about photographing cars at tracks. Larry > > J > > Jack Davis________________________________ > http://www.pentaxphotogallery.com/artists/jackdavis > http://www.photolightimages.com/ > > > ----- Original Message ----- > From: Bruce Walker <[email protected]> > To: Pentax-Discuss Mail List <[email protected]> > Cc: > Sent: Tuesday, July 17, 2012 3:31 PM > Subject: Re: PESO Red means go > > The cars were hauling ass coming straight toward me entering the > hairpin turn then heading camera-left. These two cars were likely > about 3-4 car lengths apart so the lead car was already heading left > fast while the trailing car was still pointed straight toward me. > > My shutter speed was kinda low: 1/160th. My back-of-envelope estimate > suggests that at 1/160th of a second, the lead car would move about > 2.5 cm if it was going about 30 Km/h relative to me at 45 degrees into > that turn. If the lateral smearing of the license plate is to be > believed, that agrees and is about right. Then again, if I had read the previous message, I wouldn't have had to say anything but "yeah, what he said". > > I was lucky to have anything in focus at all. I had no tripod or > monopod, too low shutter speed, and there wasn't anything obvious to > manually focus on at that low angle parallel to the road surface. I > braced the hood against the chain link fence for stability and > focussed on what I hoped were tire marks in the middle of the track. I > should have maintained the shutter at 1/250th or faster to stop the > lateral movement I think. I could have traded-off higher ISO to get > that. You really want a K-5. > > My entire catch was comprised of near-misses I think. > > Glad you found it interesting, Paul! :-) > > > On Tue, Jul 17, 2012 at 3:40 PM, Paul Stenquist <[email protected]> > wrote: >> Nice framing and exposure. However, the second car appears sharper than the >> lead. A variation in motion blur perhaps? the track seems to be in focus in >> the foreground.. That's a bit odd. Focusing on a car behind the lead >> sometimes works if that car is worthy of highlighting and the lead car is >> more obviously out of focus, but you don't quite achieve that here. >> Nevetheless, an interesting photo. >> Paul >> On Jul 17, 2012, at 12:08 PM, Bruce Walker wrote: >> >>> I haven't pixel-peeped any hi-rez images for sharpness yet, but they >>> look reasonable so far. The lens is light and quick and easy handling. >>> >>> The 2:1 zoomed-out length was an issue when I was stabilizing it using >>> its hood against the chain-link fence, but that's minor. (I'm used to >>> the internal zooming of the DA* 50-135.) AF was fast on well-lit >>> stuff, but it did the crazy near/far see-saw thing when I tried to >>> focus on something in the shade. >>> >>> It's rather slow too (f4 - f5.8) and I don't do a lot of outdoor >>> shooting these days, but that said, I did enquire from its owner if he >>> was considering selling it. :-) >>> >>> Thanks, Dave! >>> >>> >>> On Tue, Jul 17, 2012 at 9:46 AM, David J Brooks <[email protected]> wrote: >>>> Nice colours and sharpness on the follow car. >>>> >>>> Impressions of the DA F 55-300 ??? I'm Still debating on getting it. >>>> >>>> Dave >>>> >>>> On Tue, Jul 17, 2012 at 8:39 AM, Bruce Walker <[email protected]> >>>> wrote: >>>>> I was invited by my K-5 shooting friend Gerrit Visser to spectate >>>>> during "Ferrari Day" at the Canadian Tire Motor Sport Park (aka >>>>> Mosport) Monday. Gerrit also loaned me his disused DA 55-300 as I >>>>> don't have any long glass to speak of, besides my DA 50-200. >>>>> >>>>> The Ontario branch of the Ferrari Club of America books the track for >>>>> the day and members bring their own wheels to test on it. Here's one >>>>> decent shot I got where a couple of classic cars are entering Moss >>>>> Corner, the hairpin comprised of turns 5a and 5b. >>>>> >>>>> http://www.flickr.com/bruce_m_walker/7587145124/ >>>>> >>>>> It's really hard to get an unobstructed sight-line here because of >>>>> multiple safety fences. We asked a track official if we could get >>>>> closer. After determining that we'd both signed the If You Get Killed >>>>> By Flying Car Parts You Can't Sue Us waiver, he said sure. "Just be on >>>>> your toes because that's a strike zone." >>>>> >>>>> I was able to shoot through the closest chain link fence with the DA >>>>> 55-300mm to get some nice low angles like this one. This is uncropped, >>>>> btw. >>>>> >>>>> K20D, DA 55-300/4-5.8, 300mm, f11, 1/160th, ISO 200. >>>>> Lr 3.1, Ps CS5. >>>>> >>>>> -- >>>>> -bmw >>>>> >>>>> -- >>>>> PDML Pentax-Discuss Mail List >>>>> [email protected] >>>>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>>>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>>>> follow the directions. >>>> >>>> >>>> >>>> -- >>>> Documenting Life in Rural Ontario. >>>> http://www.caughtinmotion.com/ >>>> http://brooksinthecountry.blogspot.com/ >>>> York Region, Ontario, Canada >>>> >>>> -- >>>> PDML Pentax-Discuss Mail List >>>> [email protected] >>>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>>> follow the directions. >>> >>> >>> >>> -- >>> -bmw >>> >>> -- >>> PDML Pentax-Discuss Mail List >>> [email protected] >>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>> follow the directions. >> >> >> -- >> PDML Pentax-Discuss Mail List >> [email protected] >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> to UNSUBSCRIBE from the PDML, please visit the link directly above and >> follow the directions. > > > > -- > -bmw > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- Larry Colen [email protected] sent from i4est -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
