Filters and Film

[mattblucas]

Hello,

I’m a newcomer to the world of large format photography and I want to try and keep the amount of wasted slides to a minimum. I’ve been browsing this forum for a while but couldn’t really find the answers to a few questions. I would be grateful for any responses

• How much exposure compensation do I need to use for my Lee linear polarizing filter (I couldn’t find this published anywhere)?
  
• If I’m taking exposures in the 4-30sec range with Velvia 50, do I need a whole range of colour compensating filters or just one filter for general use within this shutter-speed range? Alternatively, if I’m scanning in the transparencies, can I just correct the colour cast digitally?
  
• I know this is a pretty broad issue, but how much should I use ND grad filters compared to when I shoot digital? I mainly want to photograph landscapes in LF, however, with a digital camera I often need to use graduated filters (or equivalent digital techniques) to expose the whole scene properly. If I’m using Velvia 50, does the film naturally handle shadows and highlights without the need for using ND grads as extensively as with my digital camera?

Thanks in advance for your help!
Matt

[anchored]

Exposure compensation for the Lee polarizer: 2.5 stops

Velvia 50... don't be concerned much with reciprocity color shifts of Velvia... I've used it up to 7-minute exposure times with minimal color effects. I do not use color compensating filters (except for warming filters when that effect is desired). Sounds like you're scanning and using digital editing (as I do). Any minor shifts can easily be adjusted during editing.

The use of gradiant filters will be the same as for DSLR use, or for that matter any other film use. Velvia film and digital camera ranges are very similar.

Velvia is a very poor choice for a contrasty scene, as it's a very contrasty film. Consider using different films when shadows are heavy... I would suggest the use of Provia or Astia will yield better results for such scenes.

[Joanna Carter]

How much exposure compensation do I need to use for my Lee linear polarizing filter (I couldn’t find this published anywhere)?

The usual compensation for polarising filters is 2 stops.

If I’m taking exposures in the 4-30sec range with Velvia 50, do I need a whole range of colour compensating filters or just one filter for general use within this shutter-speed range? Alternatively, if I’m scanning in the transparencies, can I just correct the colour cast digitally?

There is a chart on the Fuji Pro site that mentions using various levels of magenta compensation together with the appropriate exposure adjustment. At 30 secs, you would be looking at a 12.5M filter and 1 stop extra exposure.

Although Fuji don't recommend going further than 32 secs, I have known a friend to take a 15mins exposure, including bellows factor, eposure compensation and filters as well :-)

I know this is a pretty broad issue, but how much should I use ND grad filters compared to when I shoot digital? I mainly want to photograph landscapes in LF, however, with a digital camera I often need to use graduated filters (or equivalent digital techniques) to expose the whole scene properly. If I’m using Velvia 50, does the film naturally handle shadows and highlights without the need for using ND grads as extensively as with my digital camera?

Velvia 50 has a lot less latitude than most digital cameras, e.g. a Nikon D200 has around 7 stops of range, heavily weighted to being overexposed; whilst Velvia 50 only has around 3-3.5 stops and thus would need even more grad filtering than for a digital.

Velvia 100 is a marvellous compromise between the higly saturated 50 and Astia which is much more natural. You get around 4 stops of range and much better tolerance to reciprocity.

[anchored]

I misspoke on the filter compensation...

According to the specs published on several sales sites (unable to find on the Lee UK site, and the USA site is down):

Filter Factor Polarizer - Between 2.3 and 2.8 (approx. +1.3 stops)

This from B&H spec sheets...

[mattblucas]

Thanks very much for your responses. I will try and take all this into account on my trip tomorrow!