Comments on: Lux Light Level Chart

By: Phil Stewkesbury

Phil Stewkesbury — Mon, 08 Aug 2011 15:06:59 +0000

You’re very welcome, glad it helped.

By: Betsy

Betsy — Mon, 08 Aug 2011 14:53:31 +0000

Thank you very much for the chart. It was extremely helpful and immediately answered the question I had in mind.

By: Phil Stewkesbury

Phil Stewkesbury — Tue, 13 Oct 2009 07:32:09 +0000

Hi Tony, Thanks for dropping by. All our expertise is in IP cameras and CCTV, can I suggest you take a look at Pentax Forums they are experts in the use of cameras such as yours and have a pretty extensive forum area where I’m sure somebody will be able to answer your question better than I

By: TONY HAMPSHIRE

TONY HAMPSHIRE — Tue, 13 Oct 2009 03:34:23 +0000

I would like to know how to use a Lux Meter, which I possess, to determine F stop and shutter speeds when photographing with my camera in manual mode (Pentax dslr K20D) Is there a formula I could apply to my calculator or must I purchase a very expensive digital photographic light meter to determine ‘incident’ light as my camera only measures reflected light?

Thanks

Tony Hampshire.

By: Phil Stewkesbury

Phil Stewkesbury — Sun, 30 Aug 2009 11:33:28 +0000

Hi Premalal, You're probably looking for something from the International Commission on Illumination. They produce the original standards for lighting, such as CIE S 008/E:2001 / 8995-1:2002(E) Lighting of Work Places - Part 1: Indoor. You will probably need to purchase a formal standard document if you want to refer to the original standard information. You could try web searches based upon 'Lighting of Work Places'.

By: Premalal Fernando

Premalal Fernando — Sun, 30 Aug 2009 10:41:51 +0000

I require to know the Lux Levels in the Apparel Industry, Textile Processing & Dying Industry, Biscuit Manufacturing Industry, Knitted Gloves Manufacturing Industry & Printing Industry

By: IRE and Lux Light Levels

IRE and Lux Light Levels — Mon, 12 Jan 2009 11:38:40 +0000

[...] gain a better understanding of relative lux light levels take a look at our free chart. Share and [...]

By: Phil Stewkesbury

Phil Stewkesbury — Mon, 01 Dec 2008 19:24:59 +0000

Thanks for your comments John.

So many pitfalls in the specmanship, some manufacturers even express their low-light capability as something like 0.1 lux at 50 IRE, which to those in the know means you will get half the video signal you should get!!

Light & lenses – plenty of scope for future Posts there …

By: John

John — Mon, 01 Dec 2008 18:11:59 +0000

Hi Phil,

Good topic.

A couple of other points that are helpful when dealing with lighting:

- Vendors rate their camera in terms of minimum lux needed – 5 lux, 1 lux, .1 lux, etc
- This number is usually only for an acceptable scene, not a sharp, clear crisp scene, you often need 5x the lux for an ‘ideal scene’
- This number is usually based on a very high F stop for the lens – in other words, they assume you are using a high quality lens that passes an ideal amount of light (usually F1.2); However, in the field, your lens may only be F1.8 or F2.0, which means you could have 1/2 or 1/3 of the light that they made in their assumption – this means you may need triple the amount of light to compensate, 3 lux instead of the rated 1 lux etc.
- The number also assumes a reflexivity of the object targeted – that is how well light reflects off the object (snow is super high while blacktop roads are really low); for instance, if you are trying to see a dark color car, you may need twice the amount of light the spec calls for

It’s not uncommon that a camera rated for .1 lux actually requires 1 lux or more for proper operation given the lens you are using and the object you are trying to capture.