switchedcraigmageephotogra Posted April 24, 2005 Share Posted April 24, 2005 Ok i've got some issues with focus but that seems to be covered elsewere on the site. One thing though i cant find mention of is motion blur occuring when using flash and at high shutter speeds... <p> I've been out taking a few bmx pics with two 550ex flashes on radio triggers set in manual at 1/1 ratio. Despite the shuter speed being 1/ 250th i seem to be getting some motion blur on subjects i normally wouldnt have expected to... And really i wouldnt expect to anyway with that setup. <p> anyone any ideas or has anyone come across this before? <br> <br> Thanx for the help<div></div> Link to comment Share on other sites More sharing options...
daniel_taylor Posted April 24, 2005 Share Posted April 24, 2005 Just a guess, but...it's noon. I'd guess there's enough light to register on the sensor without the flashes. That means the flashes aren't freezing the scene. Use a higher shutter speed, like you would if you weren't using the flashes. Link to comment Share on other sites More sharing options...
peter_phan Posted April 24, 2005 Share Posted April 24, 2005 Yes, this is a situation where there is enough ambient light that motion does register because the flash is not primary light source. If the flash were the primary light source, it would easily be able to "freeze" the action. Link to comment Share on other sites More sharing options...
peter_phan Posted April 24, 2005 Share Posted April 24, 2005 By the way, at this close range, you should be able to go to FP High Speed Sync flash and use a faster shutter speed than 1/250th. Or see what you get without any flash at all, still using a shutter speed faster than 1/250th, especially shooting at noon. Link to comment Share on other sites More sharing options...
jeff_allen5 Posted April 24, 2005 Share Posted April 24, 2005 There are a few things you need to do when shooting bmx or skateboarding, or anything like this. The first thing is you need to turn your 550ex's at the most to 1/4 power, because the flash duration on 1/1 is 1/400th or so, and you need at least 1/1000 to freeze the action. The second thing is to get sharp photos your going to have to under expose the ambient by about 1 stop, so that the flash is your primary light source.Some light meters like the sekonic L358 tell you the % of flash to ambient, if your 60-70% flash you'll be ok. Also if you shooting bmx, you might want to not crop out any of the stairs or rail when your shooting, just a thought. take care jeff allen www.jeffphoto.net (there are a bunch of bmx photos on my site) if you have any questions let me know. Link to comment Share on other sites More sharing options...
steve santikarn Posted April 24, 2005 Share Posted April 24, 2005 I took this photo of a baby at 1/100th with fill-in flash using Canon 20D in the "green" mode. Is this the same problem? I get motion blurr even with the slightest movement of the hand! How come I can see the left eye through the baby's hand?<div></div> Link to comment Share on other sites More sharing options...
jim_larson1 Posted April 24, 2005 Share Posted April 24, 2005 Dumb question: You can do high speed sync with flash ratios, right? I think there is a button for it on my ST-E2. I agree with every thing else in this thread. Link to comment Share on other sites More sharing options...
switchedcraigmageephotogra Posted April 25, 2005 Author Share Posted April 25, 2005 thanx Jeff thats the most useful answer. I didnt realise the flash duration was longer at 1/1, but even at 1/400th i'd still expect it to be sharper than it is.... it's not a fast rail...<p> I've been shooting bmx for a while ;-) so have a bit of a clue, but i've just started shooting with digi and am not to happy so far.<p> I have the L-358 and from what i remember the ratio was about 60% flash so the flash was the main light... I took some pics later in the day with 3 lights and the flash was 100% the main light and i still got it, i think the guns were at 1/4 then.<p> I could have shot it sans flash but thats not what i wanted to do, also as i say the flashes were set to MANUAL so i have no control over ttl or wireless ratios or any FP option..<p> I cropped jeff to show the blur more on that upload. I'll upload one of the later ones when i'm home from work.<p> Despite this i'm having near-focus issues which are driving me crazy. Link to comment Share on other sites More sharing options...
jeff medkeff anchorage, a Posted April 25, 2005 Share Posted April 25, 2005 Sitthivet, you can see the baby's eye "through" the baby's hand because the baby's hand only obscured the eye for a small fraction of the total exposure time. Link to comment Share on other sites More sharing options...
switchedcraigmageephotogra Posted April 25, 2005 Author Share Posted April 25, 2005 another sample not to sure of the shutter speed but the flash/ambient ratio was 100% so the flash is the main light. poer of the flashes was around 1/4. Link to comment Share on other sites More sharing options...
jeff_allen5 Posted April 25, 2005 Share Posted April 25, 2005 digital will always need some sharpening...but that doesn't look right. it looks out of focus though. if they were on 1/4 power 100%, you should get some in focus frozen part at least, no matter what shutterspeed. you might want to check out skateboardphotography.com, great site, it is worth the 10 bucks it costs. Link to comment Share on other sites More sharing options...
awindsor Posted April 25, 2005 Share Posted April 25, 2005 A shutter speed of 1/250 really isn't that fast for rapidly moving subjects. If the radio slave will let you use FP mode then go ahead and use it and select a shorter exposure (though I suspect you may not be able to use FP when triggering the flashes via a radio trigger). Having said that no one has suggested the two obvious choices: namely adding a neutral density filter (a polarizer will do) and using a smaller aperture. Both will allow less ambient in and the flash will become the primary source. How much power were you using from the flashes? If it was full power you are hosed - the sun is more powerful than the flashes and no tricks will let you make the flashes the primary source. Will that much sun you should be able to use either a single flash on FP for fill or shoot with only the sunlight. In this case faster shutter speeds are available. Link to comment Share on other sites More sharing options...
jeff_allen5 Posted April 26, 2005 Share Posted April 26, 2005 fp mode cannot be used for fast moving action and will cause even more blur, because it fires lots of tiny bursts of the flash, so it causing blur for fast moving objects. Most of my shots on my site were shot in bright daylight. You just have to overpower the sun, which may sound hard, but its done all the time, go look in skateboard and bmx mags. Link to comment Share on other sites More sharing options...
switchedcraigmageephotogra Posted April 26, 2005 Author Share Posted April 26, 2005 Thanx for the link jeff i'll check it out.. yeah it is odd hey... i admit it looks a little soft on that upload but everything around that area of the rider is in focus (which is a shock with the damn focus problems i'm having with the camera, i think i manual focused that one...), the blur on him is motion blur.... you can see the movement at the edges when you zoom in. <p> I'm pretty ticked off actually as i tried a brand new camera in the local shop and it has the same focus problems so i'm guessing has the same blur problem.. What you shooting with jeff you still on film? i'm seriously considering moving back to it and buying a jobo processor for all my personal/bmx stuff.. <p> I've now been told by the camera shop i have to wait 4 weeks for a 'repair' to be done to the focusing, but i can borrow a haggard d60 in the meantime... wooo wooo :-p<p> As for overpowering the sun, it aint to hard with a couple of 500w/s bowens on a battery pack, set to full power, but they wont fit in a backpack ...doh... <p> oh and here is the original uncropped version of the top image... Link to comment Share on other sites More sharing options...
jeff_allen5 Posted April 26, 2005 Share Posted April 26, 2005 i used a 1d for a short time, but sold it because i don't feel digital is good enough for print yet...and the crop kills fisheye so i dont use it. I use a little point and shoot to check lighting sometime. Im using a Hasselblad 500cm, and a Canon 1n, I actually just purchased a Lumedyne 400watt second action pack-with 1/1500 flash duration, So at 10 feet I can get f/22! haha However, it shit the bed! and I sent it back today....owell we'll see why that happened. Link to comment Share on other sites More sharing options...
switchedcraigmageephotogra Posted April 27, 2005 Author Share Posted April 27, 2005 Ah a hasselblad, very swish, i had an RZ with a fisheye which was amazing but was a pain to lug around, so i sold it and bought some monoblocs and radio triggers... My 1n keeps lookin at me from its camera bag all sad i aint used it in ages.... :-(<p> Well the 20D's gone off to canon for a check up so we'll see in a month.. but i'll see what this loan D60 does in the meantime. Link to comment Share on other sites More sharing options...
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