PDA

View Full Version : Stopping the prop



T. Adams
03-22-2002, 10:52 AM
A question for you expert photo guys. Since I don't have the access some of you have I need to shoot with long lenses. Probably a 300mm Canon L series with a 2.0x, or a 1.4x attached to it. I know the rule of thumb to prevent blurry photos is if your length is 500mm, no slower than 1/500th shutter speed. Now my question, at what shutter speed does the prop freeze. There is nothing worse than a shot of an airplane in the air with the prop froze like it is on ground display.

T. Adams
03-22-2002, 12:02 PM
Really I don't want to stop the prop. At what speed will I be in danger of stopping it. :confused:

AAFO_WSagar
03-22-2002, 03:31 PM
Originally posted by T. Adams
Really I don't want to stop the prop. At what speed will I be in danger of stopping it. :confused: Actually, Bear is pulling *my* chain on this issue as we and most other photographers, disagree on the stopped prop issue... but that's another debate :rolleyes:

I know what the "formula" is if you shoot a 500mm then shoot at no less than 1/500 but you just have to cheat on this.

I've been using a 500mm lens with great success shooting as low as 1/250th and if you are fairly steady and follow the subject, you'll get decent results.

This photo for example was shot at 500mm but I bumped up the shutter speed to 1/350th due to there being severe wind buffeting me and bouncing the lens/camera around significantly and it's not a close in shot, Dave Morss is quite a distance away from me and if memory serves me correctly, he was moving significantly in the frame.. but the results do speak for themselves.

A lot of it depends on the prop rpm of course. A slower rpm and you'll have to drop the shutter speed correspondingly. There is a math formula, of which I dont' have handy, where you can calculate the prop rpm versus shutter speed and basically know how far the prop will move during the shutter opening. I suppose it's basic math if you know the prop rpm.. Hope this helps. pic below.

Wayne

http://www.aafo.com/gallery/week/06-25-01.jpg

Kraz
03-23-2002, 07:51 AM
I agree with Adams, 'stopped' props are for static display! The prop blur goes along way to adding the extra feel of speed and motion in the picture. Also, cranking a shutter speed of 1/1000 will stop the prop--and almost guarantee the picture is sharp (assuming the focus is good).

The challenge is slowing the shutter down to capture the relative speed of the prop without losing the crispness of the plane due to the it’s motion. The easiest shot is when the plane is more-or-less coming straight toward the camera. I have had good luck shooting at 1/250 (at 400mm) which gives about 30 degree prop blur arc (on a P51 at full speed). At 1/500 you will get only a minor blurring of the prop.

If the plane is crossing side to side, the prop blur will become less noticeable because of the orientation of the prop’s relative motion. Likewise, the shot is more difficult to capture because you have to track the subject with camera and are more prone to blurring the subject due to high zoom (and in my case—shakey hands). I usually bump the shutter speed up (and still yield quite a few blurry airplanes). The effect worsens if the subject is transitioning through focus ranges (Ie, not consistently within the infinity focus of the lens).

I just bought a Canon L series 100-400 Tele (and the digital body add a 1.6x factor to that) w/ image stabilization, which Canon advertises gives you an additional 2 stops, so I will be looking forward to the upcoming airshow season to give it a through test drive and seeing how much the props can be blurred!

Kraz~
Kraz Avian Photo (http://www.krazations.com)

AAFO_WSagar
03-23-2002, 07:58 AM
Kraz.. I've seen video you shot with a lightweight camera.. you have hands any shooter would kill for!

This is a nice shot! What speed... less than 1/60th? Tripod?

Very nice.. I love that full arc blur effect!

One-Take-Wayne

Kraz
03-23-2002, 08:07 AM
The Bonus of digital is the *extra* data encoded in the photo. For the above photo of the T-6:

Camera Model Name: Canon EOS D30
Shooting Date/Time: 9/10/2001 4:35:32 PM
Shooting Mode: Shutter Speed Priority AE
Tv (Shutter Speed): 1/20
Av (Aperture Value): 19
Metering Mode: Center-weighted averaging
Exposure Compensation: +1
ISO Speed: 100
Lens: 75.0 - 300.0 mm
Focal Length: 230.0 mm
Image Size: 2160 x 1440
Image Quality: Fine
Flash: Off
White Balance: Auto
AF Mode: AI Servo AF
Parameters:
- Contrast Normal
- Sharpness Normal
- Color Saturation Normal
File Size: 929 KB
Drive Mode: Continuous shooting
Macro: Off

AAFO_WSagar
03-23-2002, 08:17 AM
Well... did ya? If you can shoot that clean at 1/20 and not use a tripod.. Dood.. you DO have the hands of a brain surgeon! :eek:

<fancy hand drawn sigfile>
-----------------------
-One-Take-Wayne-
pushy opinionated
editor type A guy
-----------------------
</fancy hand drawn sigfile> :eek:

Kraz
03-23-2002, 08:25 AM
Naw, If I recall, I left my tripod in the office and actually I braced the camera against the crowd fence along pit row.... Took several attempts to get the right effect too-- another advantage of digital: Image review! I kept creeping up on the right combo for the full arc, but could review each shot. I also had several shakey burred shots too.

AAFO_WSagar
03-23-2002, 08:30 AM
Wait'll you turn 50... liver spots and shaky hands... :( not to mention thinning hair.... oops.. you already have that..

<ducks as he runs out of the room dodging sharp objects thrown by Kraz>

:D :eek: :)

One-take-Wayne

I've turned into a vampire.. I must return to my coffin! The bright glowing orb has risin and I'm beginning to melt!!! :cool:

T. Adams
03-23-2002, 08:31 PM
Well what a can of worms I opened. Here is my first try to post an image "prop blurred". This was shot with the cheap Canon consumer 75-300 USM zoom. I have dumped that lense, bought a 70-200 f/4L, and plan on being armed with a 300 f/4L and teleconverters at this years race. I guess I'll have to try "prop stopped" and "prop blurred". I just hope I don't get too many of the dreaded "planes blurred".:D

T. Adams
03-23-2002, 08:34 PM
Wow, something I did with a computer worked the first time. I guess it looks OK. I'm definitely no expert at Photoshop 6, and my bargin basement scanner only does a fair job.

T. Adams
03-23-2002, 08:55 PM
Well that was so much fun, here is another shot of the mighty Furias.

Kraz
03-23-2002, 10:36 PM
Mark, Now if you could get a shot that *stopped* turbine blades in flight on... say... oh.. an F-15... now, THAT would be impressive. Hmmm, let see... 50,000 rpm is aprox 1 revoution every .0012 seconds, so at 1/1000 you are still getting 300 degrees rotation of the bades.... Yeah, stop that! <grin>.


Adams, Great shot of Miss A! The painted prop tips make for a wonderful effect on that one! Keep up the great work. Also, would be interested in how your new 'L' lens does for you, especially coupled with the doubler...


Kraz
(charter member of the PBAC (Prop Blurrs are Cool) Club :)

AAFO_WSagar
03-23-2002, 10:50 PM
LOL.... don't get DABEAR started.. As soon as he sees in the manual for the D1 that one of the things it's really good at is extremely high shutter speeds. I've seen shots of water coming out of a faucet where it stopped all the dropletts of water illistrating that it's not really a "stream" but a collection of many areaited dropletts together...

And I agree.. those are nice shots by T. Adams.. as well as a nice shot by Mr. Beardood.

We'll never agree on the stopped/notstopped issue but... nice none the less.

One-Take-Wayne

wolfee
03-23-2002, 11:26 PM
Mr. adams, that is an awsome shot of Mis A.
I have on question for you,

How did you stop the star on the nose cone, and keep the prop in motion?:confused: :D

This (oohh hum) "board pilot" jumps back in to his denn to avoid the Bear.

wolfee
03-23-2002, 11:32 PM
Kraz

I can see a cool Kraz creation comming to life from this "stop the prop" topic.

what do you think?

T. Adams
03-24-2002, 07:35 AM
How did I stop the star on the prop, but not the nose? Beats the heck out of me. I just aimed and shot. My guess is probably about 1/125 to 1/250 sec. I never remember what speed I took a particular shot with, but I do pay attention to what the camera is telling me when I'm ready tom take the picture.:confused:

Kraz
03-24-2002, 09:05 AM
Wolfee, Thanks for the encouragement, but since I have to work side-by-side with Dabear in September, I don't want to have to rely on the pylon judges to officiate Bear digging my grave in the dessert! :D

As far as the stopped Star: it is actually turning too, but since it is closer to the center of the rotation point, it's relative motion is less than the prop tips. The prop tips are moving faster and further (distance traveled), creating more "blurr" the further out from the center you go....

Kraz

(Admitting that yes, sometimes stopped props ARE good <grin>!)

wolfee
03-24-2002, 09:36 AM
I have been sick for the last week and have been on some pain killers:p making me be more of a smart ass than usual. Last night I was poking fun at Da Bear:). While I was fealing...... no pain if you will:) I guess I was in my own little world and was not being clear on the point of being a smart ass.

I still think the shot of Miss A is awsome thoe, and the effect of the star being clear and the blades of the prop being blurrd is cool.


By the way I have the same problem, I just shoot the subject and not record any of the specs of the shot. when shooting fast moving action with my Minolta 7XI, I am most always shooting in Program mode or "P" for profesinal (as I like to call it). I would share some shots with you guys but I do not have a scanner and most of my stuff is not on print or a Kodak CD:(

Unregistered
03-26-2002, 04:55 PM
Since you have no control over the position the prop is stopped at, Murphy says, "It will be stopped in the least glamorous position 99 out of 100 times, and the ramaining shot will be the first/last shot on the roll with a light streak across it."

However, blurred props are never "stopped" in the wrong place.