Re: [request] Light metering app
 

If you set iso and aperture, speed will be calculated according to the lux value read from the N900 light sensor.
If you set iso and speed, aperture will be calculated.
This app mimics a real light meter, I've followed the specifications described in the earlier posts of this thread.

Did someone test if the values provided by the app are useful???

Re: [request] Light metering app
 

great app man, been waiting for this.
I will post my cameras settings later on.

Re: [request] Light metering app
 

Ok here I comes :)

Nikon D300s

ISO on EV step 1/3:
L1.0(100),L0.7,L0.3,200,250,320,400,500,640,800,10 00,1250,1600,2000,2500,3200,H0.3,H0.7,H1.0(6400)

Speed on EV step 1/3
1/8000,1/6400,1/5000,1/4000,1/3200,1/2500,1/2000,1/1600,1/1250,1/1000,1/800,1/640,1/500,1/400,1/320,1/250,1/200,1/160,1/125,1/100,1/80,1/60,1/50,1/40,1/30,1/25,1/20,1/15,1/13,1/10,1/8,1/6,1/5,1/4,1/3,1/2.5,1/2,1/1.6,1/1.3,1,1.3,1.6,2,2.5,3,4,5,6,8,10,13,15,20,25,30,bu lb

Aperture on 1/3 EV step
Nikon AF Nikkor 50 1:1.8 D
1.8,2,2.2,2.5,2.8,3.2,3.5,4,4.5,5,5.6,6.3,7.1,8,9, 10,11,13,14,16,18,20,22

Nikon AF Nikkor 35-70 1:2.8 (D or non D versions should be the same)
2.8--->22

Nikon AF Nikkor 70-210 1:4-5.6 D
4--->22,25,29,32 (on 210mm end: 36,40,45 /dx body)

hope its not confusing :)
It may be good idea try to connect sync lead from flash to n900 via 3.5 jack.
And maybe make a small GUI program for adding aditional cameras and lenses and their settings as part of this app, so anyone can easily add their own values?

ps: english is not my main language, so sorry about mistakes

edit: I`ll try to test this app against my friend light meter, sometimes next week.

Re: [request] Light metering app
 

Maybe this is a bit overkill in this moment... ;)

Good idea, i'll think about it.

Wonderful, but I think this will bring us great disappointment!!! :D

Re: [request] Light metering app
 

I disagree. If someone writes down the values from meter and from a few N900s we could build an interpolation table that could calibrate and correct values.

As long as the sensor is sensitive enough and N900s are somewhat alike (but even if not), we could build the table and actually have a meter.

Re: [request] Light metering app
 

Canon EOS 550D


ISO on EV step 1/3:

ISO 100-6.400 ( - 12800 H )
?!? Sorry I`m new in the photography business ;-P

http://de.canon.ch/For_Home/Product_..._SLR/EOS_550D/


Speed on EV step 1/3

30-1/4.000 s ( 1/2 and 1/3 steps)

Aperture on 1/3 EV step
?? Canon Objektiv EF-S 18-135mm, f/3.5-5.6 IS
http://de.canon.ch/For_Home/Product_...35mm_f3556_IS/

I hope you can help me with this Data`s as well :)

Re: [request] Light metering app
 

The :D icon is a clear sign for a joke... ;)
Calibrating a sensor it's not as easy as it seems, you need a controllable environment, but if someone can do this accurately, it will be wonderful.

Re: [request] Light metering app
 

Controllable shmontrollable. One of those adjustable window shades is fine. And a sunny day. If it's even remotely linear, only a few points are enough.

Additionally, a DSLR's metering would do fine. I'm pretty sure that all decent DSLRs have the same exposure given the same ISO and aperture and same light. Or at least very similar. Those of us with both N900 and a DSLR could post calibration tables.

If I set an Alpha and a DSomething side by side at 50mm, 3.5 aperture, ISO 100 I expect them both to give me the same or at least adjacent values for shutter. Even one step could significantly darken the image.

Re: [request] Light metering app
 

Some more Canon info for your database

Canon EOS 400D
ISO: 100, 200, 400, 800, 1600
Speed: 1/4000, 1/3200, 1/2500, 1/1600, 1/1250, 1/1000, 1/800, 1/640, 1/500, 1/400, 1/320, 1/250, 1/200, 1/160, 1/125, 1/100, 1/80, 1/60, 1/50, 1/40, 1/30, 1/25, 1/20, 1/15, 1/13, 1/10, 1/8, 1/6, 1/5, 1/4, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.3, 1.6, 2, 2.5, 3.2, 4, 5, 6, 8, 10, 13, 15, 20, 25, 30, Bulb

Canon EOS 50D
ISO: Auto, 100, 125, 160, 200, 250, 320, 400, 500, 640, 800, 1000, 1250, 1600, 2000, 2500, 3200
Speed: 1/8000, 1/6400, 1/5000, 1/4000, 1/3200, 1/2500, 1/1600, 1/1250, 1/1000, 1/800, 1/640, 1/500, 1/400, 1/320, 1/250, 1/200, 1/160, 1/125, 1/100, 1/80, 1/60, 1/50, 1/40, 1/30, 1/25, 1/20, 1/15, 1/13, 1/10, 1/8, 1/6, 1/5, 1/4, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.3, 1.6, 2, 2.5, 3.2, 4, 5, 6, 8, 10, 13, 15, 20, 25, 30, Bulb

Canon EF-S 18-55mm F3.5-5.6 IS
Apertures: 3.5, 4.0, 4.5, 5.0, 5.6, 6.3, 7.1, 8.0, 9.0, 10, 11, 13, 14, 16, 18, 20, 22

Canon EF-S 17-55mm F2.8 IS
Apertures: 2.8, 3.2, 3.5, 4.0, 4.5, 5.0, 5.6, 6.3, 7.1, 8.0, 9.0, 10, 11, 13, 14, 16, 18, 20, 22

Canon EF-S 60mm F2.8 Macro
Apertures: 2.8, 3.2, 3.5, 4.0, 4.5, 5.0, 5.6, 6.3, 7.1, 8.0, 9.0, 10, 11, 13, 14, 16, 18, 20, 22, 25, 29, 32

Canon EF 70-200mm F2.8
Apertures: 2.8, 3.2, 3.5, 4.0, 4.5, 5.0, 5.6, 6.3, 7.1, 8.0, 9.0, 10, 11, 13, 14, 16, 18, 20, 22, 25, 29, 32


Hope this helps!

Re: [request] Light metering app
 

Sorry, but I can't understand the purpose of a light meter with the same readings of a DSLR.