Reciprocity Chart for Fuji Velvia 50 RVP
One of my most favourite things to do with landscapes is to collapse many moments in time into one frame. In other words, do long exposures. I use several techniques for this, but I thought it would be good to upload a reciprocity table for Fuji’s Velvia 50 RVP.
Long exposure of the Pap of Glen Coe, Scottish Highlands
Just in case you don’t know what reciprocity is, I’ll explain. When shooting film, most folk think that the relationship between the shutter and aperture are always linked. They’re not. As you get down to longer exposures, film loses it’s sensitivity; the relationship between the shutter speed and aperture fall apart, typically once you get past 2 seconds with Velvia. Which means that if you rely on your meter, you’re going to underexpose your images. So you need to compensate.
Now, you might wonder how on earth it’s possible to generate an exposure that requires more than 2 seconds to expose. Even during sunrise when the light level is low, and you’re shooting at f22, the meter may only say 2 seconds at the lowest range. So how is it possible to shoot for longer? Simple, I use full ND filters – often stacking up to 5 stops of ND in front of the lens, so that I end up with exposures around 30 seconds or perhaps a minute of two. Coupled with a compensation factor to make sure the exposure isn’t underexposed, the exposure times will be often double that.
Click on the chart for a larger, printable version
The chart has three columns. The first shows the indicated exposure time – what the camera meter may say. The second column shows what you should actually expose at. For instance, if the meter says you should expose for 10 seconds, you should actually shot for 16 seconds. Film has lost it’s sensitivity, so you are basically adding a little bit extra on top to correct for this. There is also a third column – ‘Magenta CC Filter’. Velvia apparently goes a little green the longer you expose it, and the suggested way to correct this is to use a magenta filter. They come in different strengths as you can see on the graph. To be honest though – I’ve never seen the green cast that people talk about, so I simply don’t use this column, but it’s there if you feel you need it. Who knows, perhaps I’m green-blind!
So why do I want to shoot long exposures? For mystery, in order to create a scene that is a departure from reality. I love surreal images, and if I find a good landscape where the clouds are moving fast for instance, a long exposure allows the movement of the sky to be recorded. It can add a sense of movement or drama to an image. There are any other reasons, but generally, I tend to find the blurring of moving water, moving sky can radically change the experience of how we view the image.
Hi, whenever I use an ND filter I end up with a horrible purple colour cast effectively ruining the picture. The filter I am using is Cokin, I hear they are notorious for colour casts, but I can’t afford Lee filters at the moment. I was wondering if you have had a similar problem and if you have any advice on how to reduce the colour cast?
Comment by steveseason — 5 February, 2009 @ 4:06 am
Hi Steve,
Sorry for the late reply regarding your question about Lee filters. I’d stay away from the Cokin filters if this is what they are doing to your images.
The Lee filters are pretty true and ‘neutral’ but I have found under some circumstance that if I add too many ND grads on together, they will add that purple tone you describe. I think that’s why they haven’t made anything like a 5 stop grad due to problems with the dye’s. But if you use the Lee filters normally, there will be no issue at all. They are expensive, but in this case – you get what you pay for.
Comment by Bruce Percy — 21 February, 2009 @ 6:48 pm
Hi Steve
If you see this I hope you have sorted out your colour cast issues.
Having just seen this, I totally agree with Bruce. The cheaper Cokins’ aren’t neutral. They have now brought out the Pro series which are.
Take a look at Hitech. They are neutral and won’t cost as much as Lee. You can get them in 100m size as well like Lee.
As far as reciprocity goes, Bruce is right here. I’ve not corrected in some instances, and i have got bad colour shifts and underexposure.
Velvia 50 in its chemical makeup leans towards the reds, magentas, and yellow tones.
Comment by stevef — 23 March, 2009 @ 5:14 pm
Hi Bruce,
I’m just starting out with Fuji Velvia- just to make sure, do you recommend these longer shutter speeds for any circumstance (ie: without filters), or just for filters that lower the f-stop?
I’m an amateur photographer, and have just learned the wonders of slide film and the manual setting on my camera. I always use the meter to properly set the exposure, but I’m always looking for tips. I’d love to hear your recommendations on types of film, filters to own (I don’t own any) and how to get great shots.
Thanks,
Dan
Comment by bryantm3 — 6 April, 2010 @ 3:49 am
Hi Bryan,
It’s good timing – your posting. I’m actually working on a book about low light photography at the moment, which covers all the things you mention. I aim to release it before the end of April, so stay tuned :-)
ps. Glad you like Velvia. It is a different medium from digital, but most people don’t see the beauty of it and tend to go for convenience than aesthetics.
Comment by Bruce Percy — 6 April, 2010 @ 7:59 am