Long Exposures in Daylight?

I've done a couple long exposure shots at night with decent results, and have seen some daylight film shots that were obviously long (ish) exposures.I wish to try and shoot some myself, but I wonder just how to go about it...

 

There is danger of overexposing, yes?

Slower shutter speeds and bigger aperture numbers like F22 or 16 at 1/30 or longer? Or does aperture not matter so much, if you get the shutter speed right?

 

I have some varied films, think a couple 400 ISO (Tmax & TriX), some 100 and some 160, one roll of ISO 25, I believe. Which would work best, or is film's ISO not something one would think about here?

 

Thanks in advance!

Slow film helps, as will small (big number) apertures, but most people resort to dark neutral density filters.

I think you should use the lowest ASA film along with a neutral density filter that will allow you to use very slow shutter speeds. I would avoid going to f22, since it makes the image softer due to diffraction effect.

 

It’s better to use a decent ND filter, not the cheap ones, which produce uneven brightness in the frame.

 

To have an estimate of the ND filter you will need: under broad daylight, with ASA 100 film at f16, the optimal shutter speed is about 1/100 sec. if you want to turn that to say, 5 sec, you need to reduce the amount of light hitting the film by 500 times, or about 9 stops. The bright sunlight is about the upper limit of the amount of light hitting your camera, so 9 stops of ND is about the maximum you will need under any condition (if you want even longer exposure, you need darker filter). I would recommend three 3 Stop ND filters and stacking them together depending on light, or one 6 stop and one 3 stop, your choice.

Edited October 2, 2019 by Supriyo

+1 to ND filters. I've used an adjustable ND filter to allow long (20 second) exposures in daylight or near daylight for photographing lightning, as in this example:

This was captured with a Nikon D7100, Nikkor 18-105mm/3.5-5.6, ISO 100, f/13, 20 second exposure, and a variable ND filter at a fairly dark setting. (I don't recall the exact setting as it varied over time. I readjusted every few minutes to maintain a 20 second exposure with OK foreground and background values. the trick to capturing lightning is to keep the shutter open almost continuously. The variable ND allows this without over-exposing the scene. The bright lightning flash is sufficient to make its mark even through the filter.) A very dark (up to 9 stops or more) ND filter can be used for a variety of creative purposes. Other than lightning, one trick is using a dark ND filter plus long exposure to remove moving objects, such as cars or people, from a scene. It is much easier in digital than with film, where with film one could experience reciprocity failure. Noise remains an issue for long exposures, but can usually be mitigated in PP. Another advantage of digital over film is the ability to chimp and check exposure settings, making adjustments as light values change. For film, it would be necessary to calculate an approximate base exposure value, and then bracket extensively to accommodate any issues, including reciprocity failure. I expect slower films are less prone to this issue, but others with more knowledge will need to weigh in. If I were determined to shoot film, I think I'd experiment with various settings using my digital camera and the same lens and filter, and then use the most successful experimental value to establish my base setting(s) with film around which to bracket.

Edited October 2, 2019 by DavidTriplett

Lowering the ISO hardly gets you anywhere towards a long exposure with any noticeable effect.

 

You need an ND (neutral density) filter - a dark piece of glass that screws onto the lens and cuts the intensity of light. They come in various densities or exposure factors, from 2x (0.3D) to -12 stops (3.6D or 4096x).

 

The variable ND filters that David mentioned are good to about 6 or 7 stops (128x). Beyond that they tend to turn dark blue rather than neutral grey.

 

To work out the density you need, start with what exposure time you want, together with the aperture you'd like to use.

 

For example: A typical daylight exposure might be 1/250th @ f/8 @ 100 ISO, and you want to give an exposure of 30 seconds to blur clouds and give a streaked sky effect. 30 seconds divided by 1/250th is 250 x 30 = 7500x. So even a very dark -12 stop ND filter isn't going to do the job without using a smaller aperture than f/8. You'd have to stop down to f/11 in this case.

 

Unfortunately, such dark ND filters don't come cheap if you also want decent quality. And especially if your lens has a large filter diameter. However, there are cheap alternatives to be had from the likes of ebay sellers, which are probably OK to experiment with. The cheap filters will almost certainly add a colour cast to the shot, which can usually be improved by post-processing or manually adjusting the white balance in camera. Don't expect Auto white-balance to be of much help though.

 

Good luck!

 

Ah, I see you're intending to waste time and money shooting film. Why would you start with a high speed film rated at 400 ISO to get a long exposure? The lower the ISO you start with the better. And B&W film obviously won't care about the filter having a colour cast.

Edited October 2, 2019 by rodeo_joe|1

Thanks guys. I should have mentioned right away that I'll be doing this with the Hasselblad 500CM, so yes Joe, I'll be "wasting time and money".

Sounds like brilliant, sunlit days are not ideal, eh?

If you have a strong enough ND filter, sunlit days are doable, but..... figure that you'll need a filter factor of at least 14 for ISO 100 film at f/8 in sunlight for a minute. That's very strong! You would have to focus without the filter as you couldn't see thru one that strong, and then it's distortion might shift focus on the film plane on you, so it would be trial and error. I've tried welder's glass with only limited success.

Ricocheterider, along those lines if you use the Sunny 16 rule with 100 ISO film you will need 6 stops of light reduction to get to a 1/2 second exposure while keeping the aperture at 16. There are variable neural density filters (twin polarizers) and solid ND density filters. Either type of good quality will set you back 150-300 dollars or more. The screw in 77mm fixed density filters in my experience are more even. I use them primarily for waterfall photography but some use neutral density filters to shoot in broad daylight with a wide open aperture to control the depth of field and use a flash to light the subject. Its kind of cool actually. The alternative is to use square or rectangular resin or glass ND filters that fit in a filter holder. You can spend a lot on or a little on rectangular filters. The Hitech/Format resin/plastic filters are very affordable and are probably as truly neutral as any of the resin filters including Singh-Ray that are more than double the price. The Hitech glass filters are more pricey. I use a Cokin P-mount holder that barely accommodates a 82mm diameter lens. For the application of waterfall photography I really prefer screw in solid ND filters.

I would shoot the slowest film available starting out.

I think not mentioned yet is - Reciprocity Failure.

 

This occurs when film is exposed for short or long exposures, outside the parameters of their “typical” Exposure Time.

 

Taking the above example, if you were using Fujicolor 100, for a 30 second exposure, then you’d have to increase the overall exposure by about 1 Stop.

 

This increase in exposure is achieved by opening up the Aperture 1 Stop, and NOT by increasing the exposure Time

 

Some argue that the Exposure Latitude of most Colour Negative Film allows Reciprocity Failure to be mostly ignored, but I’ve found differently, it seems to me that the Exposure Latitude lessens when the Film is exposed for a time outside its ‘typical’. That’s my opinion based on experience with long exposures using Film and I haven’t seen data to verify.

 

You can usually find the Exposure Compensations required addressing Reciprocity Failure on the Film’s Data Sheet.

 

WW

 

PS - to address the direct question in the OP - I agree that you would need to use a lower/lowest ISO Film for long exposures in daylight, also, if using Colour Film, then do not waste money on cheap ND Filters, the Colour Cast made by some can be difficult to eradicate.

Edited October 5, 2019 by William Michael

I think not mentioned yet is - Reciprocity Failure.

Yes, I did, but your explanation is far more thorough than my mere reference. We'll done.

I read through twice and I didn't see it. I suspect my brain must have registered something for me to write "I think not mentioned yet".

Sorry for my error.

Thanks guys. I should have mentioned right away that I'll be doing this with the Hasselblad 500CM, so yes Joe, I'll be "wasting time and money".

Sounds like brilliant, sunlit days are not ideal, eh?

Joe said you use high speed film is wasting time and money. You should buy slow speed film which is cheaper and higher quality. High Speed film as the name implied is for shooting fast not for long exposure.

The first photographs took hours in daylight, but today's film is dramatically faster.

I believe Daguerreotypes have an approximate ISO of 0.01, which might give suitable times but they are a real pain to make & can't be done with a standard 35mm camera. Salt prints & Cyanotypes are easier, generally the same order of magnitude in speed, but still no good for 35mm...

 

Use the slowest ISO that is readily available, find out what the exposure is at the aperture you want to use, then see how many times you need to double the shutter speed to get to the times you want. Correct for reciprocity failure & this is the number of stops you need your filter to give. IIRC I've seen ND filters in 6-stop, 10-stop & 15 stop variants, though 10 stop is the only dark one I have.

 

You CAN use welding glass instead of ND filters - probably not a good idea for film as it gives a severe green cast. Quality isn't anywhere near as good as a proper ND filter but it allows you to try the technique for a couple of bucks.

 

Heres an example from 8 years ago with a 'shade 8' (roughly 10 stops);

Ghosts of Clacton 2 by Mike Kanssen, on Flickr

 

I have another somewhere of the sun with a 'shade 13' (roughly 17 stops). The exposure I used for that was 1/500s at f/16 & ISO200 but was actually a bit underexposed for the sun (I just used weighted metering & a 200mm lens so the sky still took up a significant part of the shot).

NB. As welding glass blocks UV & IR more than visual light it is safe to view the sun through the darker shades (unlike most 10-15 stop photographic filters).

Edited October 5, 2019 by petrochemist

For completeness here's a table of calculated equivalents for welding glass shades (that I had at work)

 

welding glass

shade factor___f-stops____ND_____Abs_____%T

2 ____________1.4_______2.7_____0.4_____37

3 ____________2.9_______7.3_____0.86____13.8

4 ____________4.3______20______1.3_______5

5 ____________5.7______52______1.7_______2

6 ____________7.1_____141______2.1_______0.8

7 ____________8.6_____380______2.6_______0.25

 

8 ____________10______1,024______3________0.1

9 ____________11.4_____2,750_____3.43______0.04

10 ___________12.87____7,400_____3.86______0.013

11 ___________14.3____20,000_____4.28______0.005

12 ___________15.7____54,000_____4.7_______0.002

13 ___________17.1___145,000_____5.14______0.0008

14 ___________18.6___390,000_____5.6_______0.00025

 

15 ___________20____1050000_____6_________0.0001

16 ___________21.4___2800000____6.4________0.00004

 

 

shade factor =7A/3 + 1

f stops = A/0.3

(ND = 2^(f stop)

T%=10^(-A)*100

 

8-14 are the most useful/common, I don't think I've ever seen shade 2 or above 14.

I suspect the shade refers to the maximum transmission allowed as the two shade 5's I've got are about a stop difference.

 

Definitely not as sharp as a photographic ND, not as repeatable, have a severe colour cast, but the normal 4x3 size fit in a Cokin P holder. Great for quick experiments IMO & very affordable. ;)

Edited October 7, 2019 by petrochemist

What subjects do you want to shoot? Why do you need such long times? Why do you have to shoot during the midday?

What subjects do you want to shoot? Why do you need such long times? Why do you have to shoot during the midday?

 

I've just seen a few images, mostly landscape stuff that had longish exposures and I liked that effect. Since I''m trying to figure stuff out,I'm curious as to how one goes about it.

I've just seen a few images, mostly landscape stuff that had longish exposures and I liked that effect. Since I''m trying to figure stuff out,I'm curious as to how one goes about it.

As explained, by using neutral density (ND) filters. Also as explained, ND filters come in a whole range of light-stopping power. To find out how much light-stopping power you need, you have to consider what the exposure without the filter might be, and by how long you want to extend the shutter speed.

 

Some suggested scenarios and the strength of filter needed:

 

Blurring slow-moving vehicles or bustling pedestrians to give an impression of speed - 1/8th to 1 second. No filter in dim light to a x16 ND (-4 stops) in bright light.

 

Turning flowing water (streams, waterfalls, cresting waves, etc.) 'milky' - between 1 and 10 seconds. X8 ND in dull light to x32 in bright light.

 

Turning fast moving traffic and pedestrians 'invisible' - 30 seconds to 1 or 2 minutes. - 10 to -12 stops

 

Making scudding clouds look like streaks in the sky - 30 seconds to 2 or more minutes. -10 to -15 stops

 

 

Turning stars into curved arcs in the night sky - minutes to hours. No filter to x32.

 

All the above assume using a small aperture (big f-number) to control the base exposure.

 

As has been previously stated; you need to decide on the effect you're trying to achieve, which dictates the exposure time needed, and work back from there to get the strength of ND filter that will allow such a long exposure.

 

A variable ND filter is probably your best starter investment, and for B&W film it doesn't matter if it's a cheap version that turns blue at high density settings.

Edited October 13, 2019 by rodeo_joe|1