Very long exposures -- daytime

[lubitel]

Hi Folks,

I would like to make some photographs of the city I live in during daytime with long exposures. I am thinking about minimum 5min and maximum 30min. How would this be possible? I'll probably be using Lubitel 166 medium format TLR. f22 and iso 50 probably won't be enough for such a long exposure even on a cloudy day.

What would you recommend?

 

[Goodyear]

A neutral density filter.

If there isn't one to fit your camera, you could rig something with a cokin- or lee-type square filter.

 

[Pherdinand]

you can also use a pinhole camera and slow film. You get extra effects with this.🙂

 

[lubitel]

I thought about pinhole, but so far my pinhole experiments had miserable results.

I'll try these neutral density filters, but then how do I calculate the exposure? Can I use these filters with color film?

 

[naturephoto1]

I am not sure of the filter size for your camera. But as has been mentioned, I would think that ND filters would be the way to go.

Though they are expensive, Bob Singh, Singh-Ray Filters makes them in different grades to fit Cokin P holders for US $99 to $225 each. These can be seen at http://www.singh-ray.com/morefilt.html . More economical would be his new rotating Vari-ND filter in 77mm thread (includes one adapter ring of your choice of 52-67mm thread): http://www.singh-ray.com/varind.html . This would be appropriate if you need different grades of ND and offers ND of from 2 to 8 stops.

Yes, ND filters can be used with color film. They are gray in color and basically just slow down the film speed. The filters have a filter factor than can be used to adjust the exposure, or you can check the adjustment in the exposure by metering with a spot meter (or possibly an averaging meter) through the filter.

The only thing is I do not believe you may not be able to get as long exposures as you would like in daytime unless you used several ND filters stacked.

Hope this proves valuable.

Rich

http://nelridge.com
richard@nelridge.com

 

[lubitel]

oh my god -- 350 dollars for a filter?
I was thinking something like 10 to 20 bucks. lol.
for 100 bucks i can buy a superb pinhole camera 🙂

 

[Hektor]

Just put a pinhole in front of your lens..........simple really............

 

[naturephoto1]

No question, expensive for the Bob's new filter. His products are expensive, but of the highest quality using the best quality glasses and or acrylic materials, and his products are very neutral for color. But it is variable, and unless, mistaken there is no other filter made like it.

You can look into some very inexpensive ND filters. I can't comment about their quality. But get the highest numbered ND filter you can find. Good quality ND filters are not cheap. I would be interested in a very high quality pin hole camera for $100.

Rich

http://www.nelridge.com
richard@nelridge.com

 

[naturephoto1]

Yes the pinhole may also work, but, be prepared for degradation of the lens performance.

Rich

 

[lubitel]

Just put a pinhole in front of your lens..........simple really............

What do you mean "in front of" ? Do you mean it is possible to put a pinhole in front of the lens, withouth removing the lens?

I'll also try to look into some inexpensive filters.

 

[Hektor]

Yes, just put a pinhole in a lens cap....you need to know how to make a good pinhole.....just drilling a hole in a plastic lens cap isn't good enough.

BTW, the pinhole doesn't degrade the lens performance..........the lens improves the pinhole's performance.....it's aperture related.

 

[XAos]

Most pinhole experiments with traditional cameras involve drilling out a body cap. To do it right, the body cap is drilled out much larger than the pinhole (but still a relatively small hole), and foil is affixed to the cap, allowing for a much thinner hole and less of a tube in a thick plastic bulkhead.

A pinhole in front of a lens would be more trouble than it was worth.

 

[naturephoto1]

Yes, you can put something in front of the lens with a pinhole including using a filter threaded into the camera lens with a pin hole (use a UV or clear filter). If using a filter directly with the pinhole (centered) use something like cardboard cut to fit the filter (will need to experiment to prevent light leaks around the edge of the filter).


Drilling through a body cap would be a great way of making a pin hole.

As pointed out by myself and others, you can stack your ND filters, preferably not beyond 2 or a maximum of 3 and try to use a hood or shade the camera lens from flare and reflections.

Rich

http://www.nelridge.com
richard@nelridge.com

 

[Hektor]

A pinhole in front of a lens would be more trouble than it was worth.

I disagree, it's exactly what he's asking for -- long time exposures at minimal cost.

Your explanation of making a pinhole is relevant.

The presence of the original camera lens gives an improvement over just using a pinhole alone.

If you want to get really 'techie', unscrew the front or rear lens element group and put in a thin disc, with a pinhole in it, adjacent to the iris blades....but it's not really necessary....just put the pinhole in front of the lens.

 

[Hektor]

Stacking ND filters can get expensive if you've got to buy them.

Pinholes are cheap.......

 

[naturephoto1]

Hektor,

Certainly the lens will improve the quality of the pinhole, but won't there be some degradation of lens performance due to diffraction?

Rich

http://www.nelridge.com
richard@nelridge.com

 

[rbiemer]

Hi Folks,

I would like to make some photographs of the city I live in during daytime with long exposures. I am thinking about minimum 5min and maximum 30min. How would this be possible? I'll probably be using Lubitel 166 medium format TLR. f22 and iso 50 probably won't be enough for such a long exposure even on a cloudy day.

What would you recommend?

I would recommend the pinhole approach. It's the least expensive and not so much trouble as you might think. I would cut a round piece of black mat-board so that it will sit squarely on the front of the taknig lens. In the center of that, cut a hole--1/4 inch or 12mm--this size is not critical--you will then need either a peice of aluminum or brass that will be cut smaller than the cardboard disk but larger than the hole in the cardboard. In the center of that peice of metal, drill the appropriate sized pin-hole.
Tape the metal to the cardboard, then tape the whole assembly to the lens.
Using a TLR camera will make framing fairly easy.
Couple of other thing you'll need to consider:
I don't recommend using a soda can for the metal as the aluminum in those cans is very hard. If you can't find brass sheet(about .002" thick), the next best choice is the aluminum "disposable" pans that store bought baked goods come in(here in the US anyway).
I use a set of very small drill bits to drill my pinholes but the most important thing is that the hole is round and smooth.
Here are a couple of links that will either help you or overwhelm you:
For general pinhole stuff there is: PINHOLE RESOURCE this site is by the author of the main book I use and lots of good stuff there(I think they sell pinholes if you don't want to makr your own)
A new one that was recommended to me by a fellow RFFer is:
MRPINHOLE I really like the calculators there a lot!
And one source of the drill bits I like(and sheet metal) is:
MICRO MARK
These should get you started.
Any questions I can help with,let me know.
Rob

 

[Hektor]

Not if the pinhole is in very thin material........and has exceptionally thin edges.

I could suggest another technique.......

Since it's a Lubitel, it uses 120 roll film....... so make up a "film" using backing paper and thinnish ordinary photographic printing paper......it's about 2 ASA.

That will give you negatives on paper which can be scanned on a flatbed and reversed into positives in something like Photoshop.

 

[Hektor]

Drilling holes is ok, but it's not the best way to make a pinhole.......

Using thin soft metal push a smallpeaked dent into it with the end of a knitting needle, Not all the way through.

Then with an emery board file of the peak until a small hole appears....the edges will be razor sharp.....just what you want for mimimum diffraction.......That's it..!

 

[rbiemer]

Not if the pinhole is in very thin material........and has exceptionally thin edges.

I could suggest another technique.......

Since it's a Lubitel, it uses 120 roll film....... so make up a "film" using backing paper and thinnish ordinary photographic printing paper......it's about 2 ASA.

That will give you negatives on paper which can be scanned on a flatbed and reversed into positives in something like Photoshop.

I like that idea, Hektor! One thing to consider when using paper is that some papers have stuff printed on the back side(brand name,etc) aside from that, this might be the easiest way for really long exposures.
Rob