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Light levels in a living room or any other room what to expect?

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Light levels in a living room or any other room what to expect?

Post by Eric M Palmer on Sun Mar 02, 2014 2:03 pm

May seem odd but in the days of film using a 600 ASA (ISO) film with a f2 lens at 28 mm I was able to take pictures indoors without a flash. I can't remember the shutter speed but with no anti-shake likely 1/20 second was slowest I could have used hand held.

Since then room lighting has changed my living room from builders had two 100W bulbs then we fitted a three bulb fitting and either 40W or 60W bulbs were used until the day of the CFL at which point we tried using ugly 11W lamps. After a refit we went to 5 bulb fittings SES and moved to 10 x 8W CFL which to be frank was a bit on the dim side then we moved to 8 x 3W + 2 x 1.4W giving 2200 lumen with these bulbs to take a picture with f3.5 18mm (28mm at 35m film) needs an ISO of 1600 to get a shutter speed of 1/30 second which means in real terms my room today is dimmer than in the days when I used tungsten lamps and a film camera.

Out of interest I tried the kitchen with 2 x 58W florescent tubes shutter speed 1/20 second and dinning room with 6 x 8W CFL and also 1/20 second although it looks dimmer than the kitchen the kitchen looks the brightest of the three rooms all readings taken at night so no daylight and lights have been on for a few hours so all warm.

So although I could take hand held with Nikon with the Pentax where the maximum ISO is 1600 with a f3.5 lens really too dark. My conclusion was lights today are darker than those used 30 years ago. However I realised my original 28 mm lens would still fit my Pentax so tried with that old lens. Unfortunately in manual the light meter does not work with the non electric coupled lens so only way was to take photos and alter shutter speed until I got right exposure. This was a surprise left camera at ISO 1600 and at wide open f2 I had to raise shutter speed to 1/90 second and still slightly over exposed.

Rather a surprise so rechecked with standard f3.5 lens and this time with polarising filter removed. Yes full stop difference so yes 1/45 second at 1600 ASA wide open at f3.5 for all rooms but with old fixed focus lens with daylight filter on f2 at 1/90 the picture was brighter than f3.5 at 1/45 with no filter so it would seem I need to find room for the lens and start using the old f2 lens again. With the f2 lens camera can be set at 800 ISO and still have 1/45 second in all rooms down stairs.

So it would seem my room is still at the same light level as 30 years ago. OK dropped from 200W to 26.8W but light level is the same. So out of interest what are the light levels in other homes? Clearly with any filters removed but would a f2 lens with a ISO of 800 allow pictures to be taken in most homes?

Eric M Palmer

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Join date : 2010-09-22

http://www.markpalmer.talktalk.net

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