how to achieve prop blur

[trevortex88]

Thanks, M.M.  Very helpful.    I'll try to remember that this weekend at London.   
Trev

[M.M.]

Since everybody else is putting up P-3s and CP-140s, I demand the right to do so, too!

This is how much blur you get from a T56 at taxi power at 1/100th.  Focal length was somewhere around 300mm, which is why I didn't go to an even lower shutter speed. 

One disadvantage to slowing down to blur the prop, as Tyson mentioned earlier, is greater depth of field.  Everything within 100 miles of your subject may be in focus.  Here the heat haze and exhaust blurred things a bit, but you can still tell those are un-military RVs in the distance.

-M.M.

[tvrphoto]

In order to combat the depth of field issue, I've been experimenting with ND filters.  If a hypothetical shutter/aperture combination results in 1/100 sec / f/22...by placing a filter that will decrease the amount of light by 3 stops, a shutter / aperture combo of 1/100 sec / f/8 should be achievable...sounds a little better eh?  This is of course assuming your camera is on shutter priority.

Just a thought for combatting the problem.  Otherwise, great shot Mark...the heat blur adds a great effect.  Nice job.

[Rotor]

Tyson -- I use ND filters on my little camera to great effect (as its minimum aperature is F8).  With an ND8 at ISO100 I usually get 1/60th at F4.5-5.6 on a nice day.  Stacking a 8, 4, and 2 gives me insanely interesting shots with 1/30th sec shots at F2.8 and the such.  ND4 or 8 usually stays on the camera as I almost always try to slow the prop and still have a wide ap.

-Mike

[mik]

the discussion had mention of dof increasing when moving the shutterspeed, god help me if i didn't understand that.

maybe i need to crack a book and i don't mind confessing my ignorance to such great shooters here. I thought  when you focus at infinity like much, (not all, like air to air and such) of  our shots are at, practically everything beyond the plane  would be in focus no matter how wide open you are? Am I confusing hyperfocal/dof at infinity/true focus distance we shot at versus little focus mark on lens?

not incidently either, great shots everyone

[tvrphoto]

That's what Program mode is for...kicking back and relaxing!

Even at infinity, stuff will still be out of fucus in the background depending on your aperture.  Furthermore, rarely is absolute infinity ever used due to the specifics of a lens.  If you get a chance to check out the larger fixed length lenses, you'll notice the infinity mark has a continuation line after it.  Lenses contract and expand distorting what infinity really is based on the ambient temperature of your environment.  The larger lenses simply exaggerate this effect making it more noticeable.

[mik]

  i meant thank god i understand the relationship between shutterspeed and aperture, though a shocking number of people selling prints don't. I confess though i put in P mode when using a flash, i mean i'm truly ignorant there

one of the things that was repeatedly told to me at photo boards when i started was that you didn't have to use  auto focus you could just set your lens to focus at infinty and get all your shots in focus, I never really trusted that advice though.

Thanks Tyson, looks like some more book learnin is in order for me.

[Rotor]

Get an ND filter, it's a must.  My Uzi maxes out at F8 as well, so I usually run either an ND4 or an ND8 filter.  With an ND4 I can usually get 1/160th in the F5.6 range, and with an ND4 I get it at about F4.  The ND4 stays on the camera most of the time, with the ND8 coming out on really bright days, or when I want to shoot a chopper (IE 1/30th, which runs F8 with an ND8 usually). 

-Mike

[RichardVM]

Sometimes I end up with the 'no prop at all' syndrome, perhaps I should add a can of flourecent paint to my camera bag!

Keep in mind the color of the prop, and the direction of light. Backlit, usually means the prop pretty much disapears at slower shutter speeds. Sometimes looks kind of eerie when a plane looks like it doesn't even have a prop. Well, unless it's a jet

Even shot with front light, a black prop can start to disapear. Tucker's prop and to a greater degree Jim LeRoy's prop. You can see the yellow portions show extremely well at around a 30th of a second, but even with frontal lighting, the black tips become transparent except for where there are specular highlights.

Richard

[Gareth Horne]

Stunning image Richard, thanks for the tip, hadn't appreciated back lit/front lit made such a difference to the props visibility. Having said that, we've been lucky to get any sunlight this year in the UK, seems to have been dull and overcast all season!

[FlyingKiwi]

...specular highlights...

Richard

Hey, Richard, keep it clean!  This is a family forum  !

Oh, hang on a minute, isn't "specular" the Dutch word for "lard"?  I think I saw that in a supermarket once.

Richard.

[skypix7]

Hi Gang:

Lots of great stuff on this board, glad to join.  Thought I'd put my two cents in.  javascript:void(0);
Helo

Generally, when I'm looking for a good prop blur, I figure it's going to have to be between 1/90th and 1/250th sec.  Typically, it's around 1/125th and 1/160th.  Something to keep in mind: when you have three or four-bladed props, you don't need to slow it down so much as each blade has to cover less distance around the circle.

Aesthetically, TVR is right: when you slow things down, you will get smaller (higher number) aperture settings to hold the exposure.  That in turn gives you deeper depth of field, which shows the background in focus.  Personally, I often prefer a good, sharp, detailed background, although it sure does depend on the shot and the location.  Often in Photoshop (I shoot all digital now) I'll take the saturation brush or some other tools and work to deepen the color and contrast of the background to give a more dramatic backdrop for the airplane.  Often I like to make the airplane smaller too, to "sell" the idea that the joy of flight lies in being suspended between heaven and earth...and both are beautiful to behold.  I'm definitely a frustrated air-to-ground shooter...would love to spend more time just shooting beautiful mother earth.
 
The three blade shot of the Piper Malibu below was 1/160th.  This shows my preference for not always having full-disc shots.  Sometimes, the blades, such as the scimitar curvey ones in that shot, look really cool when you shoot fast enough to only trace part of the arc.  It adds information about the airplane that you don't have to include in a separate ground shot of the prop, although of course you can if you want or the editor wants one.  (I shoot mostly for magazines)

My general procedure, made uniquely possible by digital cameras, is to take a test shot with the shutter speed I know I'll need for a prop blur, check it on the LCD screen, then set that speed manually for the same kind of light and bang a few off.  It gives  me good control, plus I can review instantly to make sure I got the shot and move on to the next without having to blow away too many frames for insurance, like I used to have to do with film.

Another consideration is the prop just doesn't light up in all directions.  If you don't see it with your naked eye, i.e. if it's not reflecting light as it spins, you may not see the prop.  This is something you get used to after seeing a lot of your results.  Also, profiles where the prop is seen edge-on can be cheated a little, so you can add some speed and make sure you've got a sharp airplane.  This is good on those turbulent days when you're going to get a lot of motion blurs no matter what you do. 

I did a shoot in Monument Valley last year, shooting a Cirrus SR22 out of a Cessna 172, where the turbulence had me hitting my head on the ceiling of the plane, pretty hard, every 30 seconds or so .  I shot at a slightly faster shutter speed than normal just to make sure I got anything I could use...The props had smaller disc arcs but I got the job done.  Sometimes you don't have any choice.

Keep up the good work everybody!

[skypix7]

Sticknrudder, re "easier on us all"...for me, that's part of the challenge, aided and abetted by image stabilization lenses: i.e., how slow can I shoot and still get a sharp airplane?

I was shooting the Red Bull Races at Reno from a chopper this last year on a very gusty day: 25-35mph, spilling down from the nearby mountains and gnarly. 

The chopper pilot couldn't hold the hover heading that would let me and the video guy shoot out of the right side of the eggbeater, so I had to shoot across the pilot's chest out his much smaller open window.  And that meant I couldn't acquire the target before it was in that small window and I only had about 1 to maybe 2 seconds to bang off a few shots.  Not the greatest shooting scenario.

I had already decided that the Red Bull photographer, a nice guy, was playing it safe by shooting everything at 180th sec. and up...but he didn't have any full prop arcs.  Kind of surprising for such a good shooter, and some real drama was left in the shutter speed dial. 

I decided they had all the good shots they needed and the magazine (this was for Pilot Journal) could always get plenty of those from them, so I choose to shoot everything at 1/125th manual with my Canon 100-400 IS because I wanted a sense of motion and I could afford to take the risk.  Did I mention I had to shoot at pretty much 400mm the whole time?  That woiuld dictate a handhold speed of at least 1/350 sec. or higher.  With IS, I've been able to get many good handheld shots below 1/200th, but of course the blur to sharp ratio goes up dramatically.

But I believed from  past experience I would get at least a few publishable images, and indeed, that's what I got...a few.   
It was one bumpy ride.

But the excitement of the challenge, and being able to pay it off, is what makes us better shooters, IMHO.  And the ones I got had that sense of action that I wouldn't have gotten at 180th or 22

Here's my two favorites from that chopper shoot. I may have posted these before, don't remember, if so, well, 

[Dave O'Brien]

I love that Blue Angel Herc shot,

I need a little help with these. Are helo's harder to get prop blur because the rear blade turns faster than the main rotors?

1/125-rear blades has the effect I'm after, but the main rotors aren't.

[Tonyz]

Dave...I can't remember which thread it was in, but we went into shutter speeds for helo blades.  The main rotor does indeed turn much slower than the tail rotor or just about any prop....to get full disk on a helo you are looking at less than 1/60th, many times down to 1/30th or so.  Not easy (tho some have pulled it off, and I hate them for it!)