JThompson
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Question On Prop Blur........

Mon Nov 02, 2009 10:46 am

Hi all,

I've been having difficulty getting sharp shots when trying to get Prop Blur with a subject.

All advice that I have seen says that most Lens's have their sweet spot at around Aperture f8, but to try and get some Prop Blur I use TV or M modes to get a slower Shutter speed, (I usually shoot in AV, Aperture Priority mode), which throws out the f8 Aperture, and the pic turns out way bright or way dark, and when it does looks ok, it is always soft.

I am getting a good result with the Prop Blur, but the Aperture the Camera is selecting causes the picture to be very soft, and if the shot is turning out dark, increasing the ISO may introduce noise.

So is it just my shooting technique that is causing these shots to be soft with the slower Shutter speed selected, or are there some things I am missing here with settings?

I am using a Canon 40D with a 100-400L Lens.

I apologise if this is a stupid question and there is a simple answer, but I am still new to trying to shoot in any other mode other than AV and any help will be much appreciated!

Cheers,
Jeff.
 
spencer
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RE: Question On Prop Blur........

Mon Nov 02, 2009 11:23 am

Hi Jeff, firstly it's not a silly Q. It's not an easy thing to accomplish and you've seen that first hand now. It takes a very steady hand, something I used to think I had....! So a tripod is always handy, especially on stationary ac. Perhaps get yourself a monopod for added support when things are moving? I always shoot in Tv mode for blur and M if I want to override anything. You can try compensating the aperture if things seem to be softening up (excuse the pun!). In fact I normally always have to do exactly that so the image doesn't blow out.
Spence.
EOS1D4, 7D, 30D, 100-400/4.5-5.6 L IS USM, 70-200/2.8 L IS2 USM, 17-40 f4 L USM, 24-105 f4 L IS USM, 85 f1.8 USM
 
JThompson
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RE: Question On Prop Blur........

Mon Nov 02, 2009 11:38 am

Thanks a lot Spence!

So it is mainly my shooting technique not being steady enough then....I'll have to keep working at it.

Yes I wasn't sure if I had missed something along the line somewhere, settings wise, and whether I was on the right track or not.

Thanks again Spence,

Jeff.
 
viv
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RE: Question On Prop Blur........

Mon Nov 02, 2009 12:21 pm

You are correct in using shutter priority. As long as the aperture does not get smaller than about f/11 or f/13, softness should not be a problem. If you really want to keep f/8 with a slow shutter speed, put a gray filter on the lens. This will reduce the amount of light getting through and the camera will open up the aperture to compensate.

But it does take a steady hand. This shot was at 1/40th/sec, f/13 with a 400mm lens, if I remember correctly. It was hand-held.


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dendrobatid
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RE: Question On Prop Blur........

Mon Nov 02, 2009 1:04 pm

I hate to see frozen props and as a lot of what I photograph is prop driven, I use Tv all the time keeping the shutter speed as low as I can which means that I drop the shutter speed if I am closer to the action, the 100mm end of the lens rather than a higher speed at the longer end.
Aircraft that are not moving do not present a great problem but another factor enters into the equation when the aircraft are in flight and that is the fact that, no matter how steady you are, even using a tripod, the subject will have moved during the exposure leading to a blurred subject.
It is not easy to get a full prop disc on a moving aircraft and, with digital, it is best to take more than one shot to improve your chances of success. I take plenty and expect to throw a lot of unsharp ones away, but can easily visit Cranwell where there is a steady stream of aircraft doing circuits and bumps.

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jid
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RE: Question On Prop Blur........

Mon Nov 02, 2009 1:05 pm

Jeff I find that practice makes perfect. It is a lot about technique. So I tend to practice on the more common aircraft at my local field.

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Photo © Jid Webb


I have tried tripods, monopods etc but find hand held for moving subjects is best. The above shot was a 'practice' shot, TV mode at 1/60 which gave me F16 on my 40D with a 24-105L lens. You won't get many keepers but the few you get normally make up for it.

Good luck,

Jid
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Dehowie
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RE: Question On Prop Blur........

Mon Nov 02, 2009 1:13 pm

Nice shot Viv..
IS is a major air when shhoting at lo shutter speeds so use it to your full advantage. Mode 2 while panning if you know what prop RPM there aircraft runs it can help you work out what shuter speed you need for a full disk.
IE The Dash 8 runs 1200RPM on approach so 1/20th will get you a full disk..not easy at longer focal lengths.
If the plane is taxiing or stationary then a pod or wimberley head will allow really low shutter speeds but if its flying its quite a bit harder..air to air even harder your moving as well.
Lots of respect for anyone getting full discs on air to air...always ask for max rpm for a shoot makes it a lot easier.
Not so slow Herk at 1/100th 600mm

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Photo © Darren Howie - Vortex Aviation Photography



Not quite as fast but lower shutter speed you can see the diff in the pics i really like the full disc you get but not easy to get..
1/40th 480mm handheld..

http://www.vortexaviationphotography.com/Airshow-Photography/Airshow-Downunder-2009-Avalon/blur-herk/587797738_HvPtV-X2-2.jpg

Practice practice practice...
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Ander
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RE: Question On Prop Blur........

Mon Nov 02, 2009 1:27 pm



Quoting Jid (Reply 5):
Practice practice practice...

And a bit of luck will help too  Wink)))
Cheers,
Ander
Born to tri.
 
AndyEastMids
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RE: Question On Prop Blur........

Mon Nov 02, 2009 3:10 pm



Quoting Dehowie (Reply 6):
IE The Dash 8 runs 1200RPM on approach so 1/20th will get you a full disk..

1200[RPM]/60[seconds] indeed equals 20 rotations per second, or 1/20th second per full 360 degree rotation... However, that assumes only one prop... If a four bladed prop, you will get overlap between consecutive props and thus the appearance of a full disk at 1/80 or so...

Quoting JThompson (Thread starter):
I am getting a good result with the Prop Blur, but the Aperture the Camera is selecting causes the picture to be very soft,

Maybe not soft but very slightly motion blurred due to the slow shutter speed - it can be a little difficult to tell...

Andy
 
Psych
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RE: Question On Prop Blur........

Mon Nov 02, 2009 4:37 pm

Hi Jeff.

All good advice. The only issue I would add is that I have found when shooting using Tv - which results in a small aperture - that my camera has a tendency towards overexposure more than at mid range 'f' numbers. For example, the shot below was purposely taken using Tv for prop blur, giving an f-number of 20 (and it was still 1/160th because the aircraft was taxiing relatively fast, so I needed to ensure there was no obvious motion blur):

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Photo © Paul Markman


But I needed 2/3rds of a stop underexposure, because I had found previously with bright aircraft that overexposure so often resulted (I have a 40D too).

Cheers.

Paul
 
spencer
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RE: Question On Prop Blur........

Mon Nov 02, 2009 6:02 pm

One thing I have noticed on my last two outings, trying for prop blur/full disc, was that the gazillion dust spots I have on my sensor showed up very clearly, even on the thumbnail!! Has anyone else witnessed this particualr problem, with dust spots and ultra slow Tv?
Spence.
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dendrobatid
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RE: Question On Prop Blur........

Mon Nov 02, 2009 6:55 pm



Quoting Spencer (Reply 10):
Has anyone else witnessed this particular problem, with dust spots and ultra slow Tv?

Absolutely !
Stopping the lens down dramatically really shows the dust spots up.
I even wondered about using ND filters as the lens seems softer when stopped down a lot too, though I have not yet resorted to that. I did try a circular polariser but the focussing on the 40D did not like it when fitted to a 100-400
Mick
 
spencer
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RE: Question On Prop Blur........

Mon Nov 02, 2009 7:03 pm

Thanks Mick, I actually wasn't sure if I was a. seeing things, b. going mental or c. completely messing things up!!
Now then, what would cause the dust spots to show up using a slow shutter speed (with a long focal length and stopping down)? Perhaps just more time for the light hitting the sensor to show these things up?
Spence.
EOS1D4, 7D, 30D, 100-400/4.5-5.6 L IS USM, 70-200/2.8 L IS2 USM, 17-40 f4 L USM, 24-105 f4 L IS USM, 85 f1.8 USM
 
dendrobatid
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RE: Question On Prop Blur........

Mon Nov 02, 2009 7:20 pm



Quoting Spencer (Reply 12):
Perhaps just more time for the light hitting the sensor to show these things up?

Uh ? At 3 x10 to the power of 8 metres/sec for the light, no, certainly not.

Not sure how it happens but it certainly does. I use this phenomenon to actually check the cleanliness of my sensor. I point the lens skywards and take a few shots of an even sky with the lens stopped right down.
It certainly shows up any dirt

Mick
 
spencer
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RE: Question On Prop Blur........

Mon Nov 02, 2009 7:39 pm



Quoting Dendrobatid (Reply 13):
Uh ? At 3 x10 to the power of 8 metres/sec for the light, no, certainly not.

Haha, 2.21 gigawatts and all that jazz eh Mick....and I thought I'd started drinking early! Not sure whether you meant that in jest or .... but surely a slower Tv would result in more light coming in, thus reflecting the spots onto the sensor? Or? It was actually a serious Q that I'm now really wondering over.
Spence.
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dendrobatid
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RE: Question On Prop Blur........

Mon Nov 02, 2009 8:02 pm



Quoting Spencer (Reply 14):
It was actually a serious Q that I'm now really wondering over.

I'm confused now, but would be intrigued if anyone did have an answer as to why the dust spots show more at very small apertures, but it is certainly a fact that they do.
I will throw another spanner into the works now......
They show more with long lenses too

Mick
 
spencer
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RE: Question On Prop Blur........

Mon Nov 02, 2009 8:15 pm

Agreed, long FL, stopped down and/or slow Tv.
Spence.
EOS1D4, 7D, 30D, 100-400/4.5-5.6 L IS USM, 70-200/2.8 L IS2 USM, 17-40 f4 L USM, 24-105 f4 L IS USM, 85 f1.8 USM
 
Silver1SWA
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RE: Question On Prop Blur........

Mon Nov 02, 2009 8:20 pm



Quoting Dendrobatid (Reply 15):
but would be intrigued if anyone did have an answer as to why the dust spots show more at very small apertures, but it is certainly a fact that they do.

I always assumed it was related to depth of field...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
Psych
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RE: Question On Prop Blur........

Mon Nov 02, 2009 8:48 pm



Quoting Dendrobatid (Reply 15):

I'm confused now, but would be intrigued if anyone did have an answer as to why the dust spots show more at very small apertures, but it is certainly a fact that they do.

Me too Mick.

I assume it has to be related to depth of field and light. Imagine shooting an image through a wire fence: with an aperture large enough you can almost 'hide' the wire due to the tiny depth of field, so that at worst it is a grey blur. But with a very small aperture the wire in front of the lens becomes very obtrusive, blocking more light to the camera. I assume it is the same kind of effect, but on the other side of the lens. With a very small aperture a speck of dust covers some of the light sensitive cells of the sensor and really shows, whereas with a large aperture it gets disguised a lot more.

I may be off beam here, but I am certainly taxing my brain cellls!

Cheers.

Paul
 
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RE: Question On Prop Blur........

Mon Nov 02, 2009 8:50 pm



Quoting Psych (Reply 18):
I assume it has to be related to depth of field and light. Imagine shooting an image through a wire fence: with an aperture large enough you can almost 'hide' the wire due to the tiny depth of field, so that at worst it is a grey blur. But with a very small aperture the wire in front of the lens becomes very obtrusive, blocking more light to the camera. I assume it is the same kind of effect, but on the other side of the lens. With a very small aperture a speck of dust covers some of the light sensitive cells of the sensor and really shows, whereas with a large aperture it gets disguised a lot more.

Exactly how I was thinking.
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
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dvincent
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RE: Question On Prop Blur........

Mon Nov 02, 2009 9:06 pm



Quoting Dendrobatid (Reply 15):
I'm confused now, but would be intrigued if anyone did have an answer as to why the dust spots show more at very small apertures, but it is certainly a fact that they do.
I will throw another spanner into the works now......
They show more with long lenses too

You're not really seeing the dust spot itself, you're actually seeing a shadow from the dust spot being cast as it sits on top of the low pass filter. The shadow becomes less diffuse (more in focus) as you stop down due to the narrower light source. There's some good discussions on this out there. Paul's analogy is actually spot on, it's a similar effect except with the object in front of the lens instead of behind it.

If you don't have any ND filters, a polarizer will generally act as one in a pinch; most cut out 1 1/3 to 1 2/3rds stops of light.
From the Mind of Minolta
 
Psych
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RE: Question On Prop Blur........

Mon Nov 02, 2009 9:33 pm



Quoting Dvincent (Reply 20):
You're not really seeing the dust spot itself, you're actually seeing a shadow from the dust spot being cast as it sits on top of the low pass filter. The shadow becomes less diffuse (more in focus) as you stop down due to the narrower light source.

Than makes complete sense to me Dan - thanks for that! I can relax now  wink .

Paul
 
f4wso
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RE: Question On Prop Blur........

Tue Nov 03, 2009 1:02 am

Another aspect of this topic is the speed of the propeller. Photographing during the runup versus the taxi out will yield more blur at a faster shutter speed. Likewise, takeoff propellers will be spinning faster than those in a landing configuration.

Gary,
Cottage Grove, MN, USA
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JThompson
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RE: Question On Prop Blur........

Tue Nov 03, 2009 6:38 am

Thanks a lot for all the replies fellas!

I appreciate all the info and tips that have been posted, I will take all of it onboard, and all those shots that you guys posted for examples are fantastic!

I'll keep plugging away at it, and hopefully I can finally get that shot with some nice Prop Blur without the out of focus look or soft.


Cheers,
Jeff.
 
mjlewis
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RE: Question On Prop Blur........

Mon Nov 09, 2009 3:35 am

Sorry I'm replying to this fairly late in the discussion, but found it to be VERY interesting and helpful, as I just recently had to deal with all this prop blur stuff at the AOPA Summit here in Tampa, and I was trying to shoot some of the GA planes on approach and landing, and get some decent panning shots down. Got maybe a handful of worthy "sharp" ones, but the rest were kept that were halfway decent.

The majority of them were shot at about 1/125-1/100 or so. Used my 70-300 VR so the focal lengths were all over the place, I'll post some up soon!
Flying runs in the family : )
 
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cpd
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RE: Question On Prop Blur........

Mon Nov 09, 2009 4:00 am



Quoting Mjlewis (Reply 24):
The majority of them were shot at about 1/125-1/100 or so. Used my 70-300 VR so the focal lengths were all over the place, I'll post some up soon!

That's a good shutter speed to use - with 70-300mm, VR and some practice, you'll be getting those kinds of photos much more regularly.

1/60sec and lower is a bit more difficult.
 
sulman
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RE: Question On Prop Blur........

Fri Nov 13, 2009 2:10 pm

I'm utterly hopeless at slow shutter speed stuff. Just don't have the steady hands for it. Still, it's very rewarding when it does work out.

James
It takes a big man to admit they are wrong, and I am not a big man.
 
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ptrjong
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RE: Question On Prop Blur........

Fri Nov 13, 2009 3:40 pm



Quoting Viv (Reply 3):

Wonderful picture that is, Viv.


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I had lots of time to figure out this one and found I needed to go down to 1/13th for a full circle, which in turn meant a horrible (for my 70-300VR) f/25 even at ISO 100. Obviously, such shots will often be not sharp and you should shoot a lot of frames. If you care to get a good shot of that aircraft, take a few with a less ambitious shutter speed first.

Peter Smile
The only difference between me and a madman is that I am not mad (Salvador Dali)
 
JThompson
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RE: Question On Prop Blur........

Sat Nov 14, 2009 12:29 pm

Nice shot Peter!


Cheers,
Jeff.
 
viv
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RE: Question On Prop Blur........

Sat Nov 14, 2009 1:19 pm



Quoting Ptrjong (Reply 27):
f/25 even at ISO 100.

That's why a darkening gray filter comes in handy.
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cpd
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RE: Question On Prop Blur........

Sat Nov 14, 2009 1:55 pm



Quoting Sulman (Reply 26):
I'm utterly hopeless at slow shutter speed stuff. Just don't have the steady hands for it. Still, it's very rewarding when it does work out.

James

Use a VR/IS equipped lens and a tripod. I did it today, VR on, using a new tripod with a good 3-way head and some amazingly low shutter speeds that I'd dare not use before. It's just practice. The more you practice it, the better your results will be.
 
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ptrjong
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RE: Question On Prop Blur........

Sat Nov 14, 2009 2:19 pm



Quoting Viv (Reply 29):
That's why a darkening gray filter comes in handy.

What's that, it simply takes some light out?
The only difference between me and a madman is that I am not mad (Salvador Dali)
 
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cpd
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RE: Question On Prop Blur........

Sat Nov 14, 2009 2:25 pm



Quoting Ptrjong (Reply 31):
What's that, it simply takes some light out?

Yes, that's right. Use them to get those motion blurred people walking across a scene in daylight kind of photos.

I don't know if there are any available for very big lenses - or at least, I've not seen them. I would prefer to use something like that other than F/16 to achieve the low shutter speed that I want.
 
Astro777lover
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RE: Question On Prop Blur........

Sat Nov 14, 2009 3:25 pm



Quoting Cpd (Reply 32):

Also couldn't you use a polarizing filter? Is it the same thing?

-Austin
 
viv
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RE: Question On Prop Blur........

Sat Nov 14, 2009 4:40 pm



Quoting Astro777lover (Reply 33):
Also couldn't you use a polarizing filter? Is it the same thing?

Not the same thing.

Quoting Cpd (Reply 32):
I don't know if there are any available for very big lenses

I have one that is 77 mm in diameter. Don't know if bigger ones are available.
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Astro777lover
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RE: Question On Prop Blur........

Sat Nov 14, 2009 5:46 pm



Quoting Viv (Reply 34):
Not the same thing.

Oh i didn't know they were talking about a ND filter.
 
Ander
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RE: Question On Prop Blur........

Sat Nov 14, 2009 6:42 pm



Quoting Viv (Reply 34):
Quoting Cpd (Reply 32):
I don't know if there are any available for very big lenses

I have one that is 77 mm in diameter. Don't know if bigger ones are available.

Of course. For big lenses you can use a 52 mm filter that you insert in the drop in filter holder, that you fit in the middle of the lens. Same thing applies for the polarizer.

Cheers,

Ander
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cpd
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RE: Question On Prop Blur........

Sun Nov 15, 2009 12:18 am



Quoting Ander (Reply 36):
Of course. For big lenses you can use a 52 mm filter that you insert in the drop in filter holder

I know about the polarising filter, that's a very costly special item (an actual entire drop in thing that is externally adjustable. Didn't know about a drop-in ND though. I'll have to start looking.  Smile
 
Dehowie
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RE: Question On Prop Blur........

Sun Nov 15, 2009 4:52 am

ISO 50 helps...

 Big grin
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cpd
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RE: Question On Prop Blur........

Sun Nov 15, 2009 5:42 am



Quoting Dehowie (Reply 38):
ISO 50 helps...

Oh go away you...  Wink

You and your Canon stuff. Big grin
 
Astro777lover
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RE: Question On Prop Blur........

Sun Nov 15, 2009 6:13 am



Quoting Cpd (Reply 39):
You and your Canon stuff

I wish i had iso 50, that would come in handy sometimes
 
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cpd
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RE: Question On Prop Blur........

Sun Nov 15, 2009 6:31 am



Quoting Astro777lover (Reply 40):
I wish i had iso 50, that would come in handy sometimes

Yeah I know. Darren has got me this time.  Wink I would have liked to have had it yesterday, instead of using F/14. The results at F/14 were still sharp and had no hint of softness - but those aperture settings show up every hint of dust.
 
mjlewis
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RE: Question On Prop Blur........

Sun Nov 15, 2009 4:57 pm

With some cameras, like my D300, we can go into the LO#.# iso, same with HI's, but it's just not the same...
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dvincent
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RE: Question On Prop Blur........

Mon Nov 16, 2009 1:53 am

Keep in mind that ISO 50 on the Canon 5D/2 is not a "real" ISO, it's just a one stop underexposure that's pulled back via a tone curve. You could get the exact same exposure by doing EV +1 and then pulling back by one stop in RAW. You will lose some dynamic range, but it works.

This also goes for ISO 100 on many cameras using Sony's 12 MP CMOS or 6 MP CCD (NIkon D300/s, Sony a700, D90, D40, KM 5D, and on and on and on). It's basically the opposite of the boosted ISOs in the upper range.
From the Mind of Minolta
 
RonS
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RE: Question On Prop Blur........

Mon Nov 16, 2009 3:32 am



Quoting Ander (Reply 36):
Cheers,

Ander

The man with the most amazing disk rotor blades! I love his shots, some of the best I've seen.

Speaking of which though, I caught a helicopter today, used 1/80th and the rotor blade is not close to a full disk. At the time the helicopter was airborne, just after takeoff and pulling away foward.

Was my shutter speed to fast or was the RPM of the blades to slow?

Thanks
All opinions expressed by me are my own opinions & do not represent the opinions in any way of my employers.
 
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dvincent
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RE: Question On Prop Blur........

Mon Nov 16, 2009 3:43 am

Quoting RonS (Reply 44):
Was my shutter speed to fast or was the RPM of the blades to slow?

Probably both. Chopper rotors operate in the same area of RPM at all phases of flight and their rotation is quite slow - only a few hundred RPM. Given that there's usually two to four blades to a rotor, it may be tough to get a full disk without going to very very low speeds.

What kind of chopper was it?

[Edited 2009-11-15 19:46:54 by dvincent]
From the Mind of Minolta
 
RonS
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RE: Question On Prop Blur........

Mon Nov 16, 2009 3:51 am

Hey Dan...it was one of those AEROSPATIALE or however you spell it. Not to be confused with the clothing line  Smile

http://www.airliners.net/addphotos/b...2155stellan406lh111509img_2431.jpg
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dvincent
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RE: Question On Prop Blur........

Mon Nov 16, 2009 3:56 am

Yeah, I know those guys.

The main rotor turns at just under 400 RPM. That's about 6.667 (rounded) revolutions per second. Given that the 355F1 has a triple blade rotor, you'd have to have a speed of about... 1/18s to get a full disk. Since your camera probably doesn't go to that speed, you'd be looking more at 1/15s.

Still a fantastic shot, by the way.

[Edited 2009-11-15 19:58:14 by dvincent]
From the Mind of Minolta
 
sovietjet
Posts: 2549
Joined: Sat Mar 15, 2003 12:32 am

RE: Question On Prop Blur........

Mon Nov 16, 2009 5:29 am

Ander, what speeds did you use for those chopper shots with a full disk?
 
Ander
Posts: 349
Joined: Sat Jan 22, 2005 7:14 pm

RE: Question On Prop Blur........

Mon Nov 16, 2009 9:14 am



Quoting Dvincent (Reply 47):
you'd be looking more at 1/15s.

Ivan, that is the speed I used for the Swiss helos.
The Cougar and the Alouette have very "slow" rotors.

As I wrote in a previous post, luck plays an important role here.
At such speeds there are many factors that are beyond your control, as the various rotations of the airframe in its three axis or the pure shake of the frame. The cougar is a very shaky helicopter with that huge rotor on top and at 1/15 sec. the shake seems to be noticeable even if the helicopter is in stationary flght.

I can assure I took around 200 shots of the helicopters on the base turn coming back from Axalp, but only a few came out decently, so yes, a bit of luck is needed. Of course, the more you practice, the more chances you have to get a good clean shot.

Cheers,

Ander
Born to tri.

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