Problems in the sun with motion blur

I'm having big problems in trying to achieve motion blur in bright conditions.

Photo 1 was taken 1/32 sec, f2.8 iso 100 on manual, me experimenting.
Photo 2 was taken on P at 1/32 sec f25 iso 1000.

I can see neither are perfect. With mine on manual, it's pretty much a total 'white out'. Picture 2 shows more detail but no motion.

I am trying to get some blur of the wind blown grass which grows to about 30" tall. The area was torched by a couple of idiots that burned down about 30 acres of heathland. The grass is coming back but much will be beyond repair. With the 'charcoaled' branches of the small trees and some motion blur of the tall grass, I think, in the right hands there are some dramatic shots available.

So, please, how can I expose longer to achieve blur without getting the wipeout, or should I shoot in less bright conditions?

Thanks for any input from a well confused newbie.

Simon.

You probably need a neutral density filter. There's too much light in the middle of the day to get a long enough shutter speed without blowing it out.

For starters, put your camera on manual. Set it to ISO 100 (or 50 if it allows), f/32, and adjust the shutter speed to get a good exposure. If that shutter speed isn't slow enough for the effect you want, you'll need an ND filter to reduce the light.

According to the exif, photo 2 was 1/320th of a second at ISO 1000. If you dropped that ISO to 100, you would get the 1/32 shutter speed you had in the first shot, but correctly exposed. However, that first shot doesn't show much blur either, so you aren't going to get much more.

If your camera has the ISO 50 expansion capability, that would drop you to 1/16th second but you aren't going to get past that without either shooting when there is less light, such as in the evening or early morning, or using some means of reducing the light reaching the sensor. A CPL (polariser) filter will drop you maybe 2 stops, giving you 1/8th second at ISO 100 or 1/4 at ISO 50. If you want to go slower still, you will need an ND (neutral density) filter, these come in various strengths and will let you drop the shutter speed much further.

If going with the "shoot when there is less light" option, use the lowest ISO you can, the smallest aperture (biggest number) and see what shutter speed you can get. If you want to use an auto mode, use Av and not P.

Biggest problem with the first shot is that it is over-exposed. Biggest problem with the second shot is that it is under-exposed.

If 1/320, f/25, iso 1000 is slighty under-exposed then I would assume 1/320, f/22, ISO 800 would be properly exposed. So lets start with that as our "proper" exposure.

You want to shoot a slower shutter speed to get motion blur in the grass. So you would want to cut back shutter speed 4 stops to 1/40 (320, 160, 80, 40 = 4). You would then need to let in 4 more stops of light by opening up the aperture 4 stops as well, to f/5.6 (f/16, f/11, f/8, f/5.6 = 4).

That should work, but I assume you are looking for less depth of field based on your first shot. So lets open the aperture 2 more stops to f/2.8 (f/4, f/2.8 = 2). To do this you need to cut back on light a/o sensitivity. In this case we can just drop the ISO 2 stops to 200 (400, 200 = 2), and you are set.

That also should work, but it may be that 1/40 is still too fast to get the motion blur you want. So you could drop it as low as 1/20 by dropping ISO to 100.

arentol wrote in post #14269752
You want to shoot a slower shutter speed to get motion blur in the grass. So you would want to cut back shutter speed 4 stops to 1/40 (320, 160, 80, 40 = 4). You would then need to let in 4 more stops of light by opening up the aperture 4 stops as well, to f/5.6 (f/16, f/11, f/8, f/5.6 = 4).

That should work, but I assume you are looking for less depth of field based on your first shot. So lets open the aperture 2 more stops to f/2.8 (f/4, f/2.8 = 2). To do this you need to cut back on light a/o sensitivity. In this case we can just drop the ISO 2 stops to 200 (400, 200 = 2), and you are set.

That also should work, but it may be that 1/40 is still too fast to get the motion blur you want. So you could drop it as low as 1/20 by dropping ISO to 100.

You would be waaaay over exposed with those settings, you moved the aperture the wrong way to compensate for the slower shutter speeds. Instead of f/5.6 you would need to go to f/64

Then dropping the ISO three stops to 100 would bring that back to f/22, which is where we started and the shutter speed still isn't slow enough. No way are they going to be able to get f/2.8 for shallow DoF.

Oh, "If 1/320, f/25, iso 1000 is slighty under-exposed then I would assume 1/320, f/22, ISO 800 would be properly exposed. So lets start with that as our "proper" exposure." is wrong too. You have opened the aperture and decreased ISO which cancel each other out, so exposure would be the same.

You need to use a neutral density filter...the strength will depend upon the amount of available light as well as how much motion blur you want in the foreground. This will also keep you away from having to use ridiculously small apertures such as f/32, etc.

Wow, thanks for the reply's guys, as quite often differing views. Firstly, would, as Mike suggested that I use an N D Filter, would that affect any of your other suggestions?

Thanks
Simon.

Dj Silver wrote in post #14270153
Wow, thanks for the reply's guys, as quite often differing views. Firstly, would, as Mike suggested that I use an N D Filter, would that affect any of your other suggestions?

Not really, no.

You are still going to want a low ISO and a small aperture such as f/22 (although if you can manage f/16, or even f/11, with a ND filter that would be better as it cuts down on diffraction softness, although that may not be an issue with a shot showing a lot of motion blur anyway, if there is nothing you want razor sharp as a counterpoint).

You will normally only use a ND filter if you are stopped down as far as you can, at lowest ISO, and still can't get your shutter slow enough. You may want one if you decide that you need a wide aperture though, for shallow DoF as well, and that would mean speeding your shutter up too much.

If you learn your way around the exposure triangle, which way to move each parameter to keep a constant exposure, and which end of the scales is "more light" and which less, it becomes quite straightforward.

Dj Silver wrote in post #14270153
Wow, thanks for the reply's guys, as quite often differing views. Firstly, would, as Mike suggested that I use an N D Filter, would that affect any of your other suggestions?

Thanks
Simon.

Using an ND filter for motion blur in bright light is the "standard" and, typically the best approach; in fact it's the only way to get slow enough speeds for some things.

But you really need to take time to understand the functions of your exposure settings -- you were "all over the map" in your shots, so first get a grip on the three settings and what they will do for your exposure. Then, yes, add an ND filter to your kit if this is an important thing for you to "capture".

A good place to start reading is this POTN "sticky":

https://photography-on-the.net/forum/showthre​ad.php?t=414088

And then, I'd advise quickly ordering a copy of "Understanding Exposure, Third Edition" by Bryan Peterson. It's a good read that can open your eyes to what you are doing!

If you're going for a long exposure, there is no reason at all to raise your ISO higher than whatever the lowest setting (usually 100) that your camera allows. You're controlling the light via shutter speed for those types of shots; so, set your ISO as low as allowed, adjust your aperture for the depth of field you want and then set the exposure by adjusting the shutter speed until a correct exposure is obtained. If you cannot get your shutter speed to go as long as you would like to get the motion, then you would need an ND filter, as some folks mentioned.

You CAN also crank your aperture way down (f/22 - f/32 for most lenses) if you're still getting too much light; but I'd recommend a strong ND over going that route for most situations.

I would also second Tony's suggested reading, there, as it looks like you're not quite understanding how exposure works; and how the three settings relate to each other or your final output.

Why? Have you thought of waiting until just before a storm when...
1. the light level will be lower, and
2. the wind will be blowing harder?

tonylong wrote in post #14270706
A good place to start reading is this POTN "sticky":

https://photography-on-the.net/forum/showthre​ad.php?t=414088

And then, I'd advise quickly ordering a copy of "Understanding Exposure, Third Edition" by Bryan Peterson. It's a good read that can open your eyes to what you are doing!

Thanks I will. I've got the David D. Busch book on the 7D and am ploughing through that but there is so much to take on board. I suppose though, that's the good thing about all this, in that you can't just buy a good camera and hey presto - award winning photos. You have to research, practise and practise again.

Thanks.

tonylong wrote in post #14270706
Using an ND filter for motion blur in bright light is the "standard" and, typically the best approach; in fact it's the only way to get slow enough speeds for some things.

But you really need to take time to understand the functions of your exposure settings -- you were "all over the map" in your shots, so first get a grip on the three settings and what they will do for your exposure. Then, yes, add an ND filter to your kit if this is an important thing for you to "capture".

A good place to start reading is this POTN "sticky":

https://photography-on-the.net/forum/showthre​ad.php?t=414088

And then, I'd advise quickly ordering a copy of "Understanding Exposure, Third Edition" by Bryan Peterson. It's a good read that can open your eyes to what you are doing!

It's arrived!!! Many thanks for the heads up.

Dj Silver wrote in post #14297427
It's arrived!!! Many thanks for the heads up.

Good for you!! Many people here have gotten a real "leg up" from reading that book, a great addition to your library!