Creating motion blur for a spinning object?

So here's my dilemma; as you can see in the picture below, my girlfriend was playing with one of my props, so I turned my lights on to play. As we know, speedlights freeze motion even at pretty low shutter speeds. However, the pinwheel should be spinning with the person in focus. I can't think of a good lighting solution to this (if anyone has one, by all means, speak up), so I tried photoshop to add motion blur (and use a layer mask to mask out everything but the pinwheel). However, nothing I do looks natural. Any suggestions/attempts with explanation would be much appreciated.

I am no expert, but I'll give it my best educated guess. First, you are going to need a longer shutter speed to get the motion blur of the prop. Also, to freeze the subject I believe that you'll want to use the second curtain flash so the flash will be fired at the end of the exposure rather then the beginning.

If I am incorrect I apologize and I'm certain someone will know and correct me.

Nick

In Photoshop:
Duplicate layer. Select the wheel (whole circle, not just the wheel itself). Apply Radial blur. Apply mask to reveal original picture where you do not want the blur.

I did a 1 minute job so not very clean but you get the idea.

Thanks.

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Baadil wrote in post #9968290
In Photoshop:
Duplicate layer. Select the wheel (whole circle, not just the wheel itself). Apply Radial blur. Apply mask to reveal original picture where you do not want the blur.

I did a 1 minute job so not very clean but you get the idea.

Thanks.

Oooooh, RADIAL blur. I overlooked that because I can't remember the last time I used it. Thank you so much, it's exactly what I was looking for. Thank you too amd is the best. If I had more ambient light 2nd curtain would probably work, but in my usual conditions the shutter speed would just be too long.

As soon as I posted I thought about using distort:twirl, and while it wasn't the effect I'm looking for, I found it kinda neat:

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Wouldn't 2nd curtain work, and still get the detail in the fan?

bulldogg7 wrote in post #9968474
Wouldn't 2nd curtain work, and still get the detail in the fan?

I'll give it a shot in the next day or two, but with the amount of ambient light I have, I'd be looking at a 5 second or so shutter speed I think.

First or second curtain sync (note that second curtain generally is only an option when using an ETTL flash) won't matter zilch for the amount of motion. It will only change wether the motion is trailing or leading.

The image you posted in post #1 was shot at 1/125 sec, f/8, ISO 100.

If this is an unedited image, you should get some motion at 1/30 or so (I see a bit already, but that might have been added in PS).

Otherwise, lower the flash output two stops, use ISO 400, f/8 and 1/30s: That gives you 4 stops more ambient with the same flash exposure

By the way, the image you posted is AdobeRGB. Us sRGB for web.

Baadil wrote in post #9968290
In Photoshop:
Duplicate layer. Select the wheel (whole circle, not just the wheel itself).

That will also blur the teeth into the "blades" and blur the tshirt (as can be seen)

René Damkot wrote in post #9968670
That will also blur the teeth into the "blades" and blur the tshirt (as can be seen)

Yes, you need to first cut out the wheel neatly and copy that onto a new layer, masking won't work as blurring will pull pixels from behind the mask.

Then you also need to clone the edges off the wheel on the background image, replacing with t-shirt and face etc.

Like this but neater.

Byte size: ZERO | Content warning: NOT AN IMAGE

Thanks for the suggestions. The picture is unedited, and I was wondering why it looked funky Rene, so thank you for the color space awareness. I must have typed something by accident in photoshop, because sRGB was always my default output. I know I can cut my power to a quarter if I need to, I just have this strange thing about going over ISO 200 in my head, even though I know my 50D is perfectly clean up to 800.

And that's a very nice job hank. Makes me think I'd really be best off to just get this closer to how I want in camera than spend 15-20 minutes on a client's picture to try and pull it off. I have someone booked for tomorrow for a full hour that won't mind me fiddling with the lights just a little bit, so I'll give the suggestions a shot and see how it goes.

René Damkot wrote in post #9968670
That will also blur the teeth into the "blades" and blur the tshirt (as can be seen)

Yes, for sure. And in my case it did blur these but this is why I added a mask and painted with low opacity to remove unwanted blur.

Would the same "Radial Blur" trick be able to add motion blur to motorbike wheels? I'm thinking of some shots of MotoGP bikes where the shutter speed was too fast and the alloy wheels have frozen rigid.

The wheels are shot from an angle, so more elipse shaped than circular. Would that rule it out?

It could be done but if the shutter speed was high enough to freeze the wheels then the background would probably not show much motion either so it would look odd just doing the wheels. Doing the background as well would be a big job and very tricky to pull off.

Hank,

I can do the background seperately using directional blur and have got one or two very believable images if were not for the frozen wheels! Yes you are right, it is a lot of work and only feasable if the shot is otherwise worth it.

In that case, a few things to remember. The radial blur works from the centre of the selection or image if nothing is selected so make sure you get the centre on the wheel hub. Sounds obvious but it's a common error. Also don't forget that the track behind the wheel with need the same directional blur as the rest of the background and the track would be visible behind the whole of the inner wheel, so you will need to completely clone out the spokes to show the track then on a separate layer, reintroduce the spokes and perform the radial blur.