Recommend me an affordable light meter.

Started Jun 26, 2013 | Discussions thread
Barrie Davis
Barrie Davis Forum Pro • Posts: 21,460
Re: Accuracy of settings

Sailor Blue wrote:

Barrie Davis wrote:

Sailor Blue wrote:

Digital is hands down is easier to read - an absolute 0.1 stop readout vs a guessed 0.2 stops.

Unfortunately, this "accuracy" cannot be transferred to the camera. When in manual mode, which must be used with the meter, the maximum degree of discrimination between aperture settings is 1/3 stop (0.33).

It is true that cameras can only be set to 1/3 stop exposure increments. When shooting ambient I usually set my L-358 to read out in 1/3 stop increments for this very reason. If I forget I don't worry since after 50 years as an amateur photographer and a professional chemist I'm pretty fast at interpolating a meter reading of 5.6 8 as being closer to f/7.1 than f/6.3 or f/8.


Speedlights I have encountered cannot be set any finer than 1/3 stop either, except by moving the light nearer/further by very small degrees, which is an irksome procedure and appears extremely amateurish while being carried out in front of clients.

With studio strobes I use the meter in 1/10 stop mode and adjust the studio strobe power to 1/10th stop.

My Nissin Di855 has three clicks of power adjustment between each 1/3 stop. In effect it adjusts in 1/9th stop. I believe Canon flashes are the same but I have no idea about Nikon or other brands.

While we are at it.....

In Manual mode the shutter speed setting of the camera is also restricted to 1/3 stop increments. Auto settings, on the other hand, have continuously variable shutter speeds (A mode)and are therefore potentially capable of more accurately set exposure than is Manual mode.

This is interesting. My understanding was that aperture, shutter speed and ISO were adjusted in 1/3 stops when in Auto mode, just like in Manual mode. Can you please provide some reference to the shutter speed being adjusted in finer increments when in auto mode.

If you take a look at the EXIF when shooting in "A" mode it often says something like 728/1000, which presumably means 728 milliseconds... which is to say, not quite 750 milliseconds [not quite 3/4 sec].

Timing is, after all, done by a chip. This is not to say the shutter actually manages to deliver the nominal accuracy, but presumably it does its mechanical best.

Or are you saying you have not yet seen that kind of fine descrimination of shutter speed?

Perhaps it depends on the actual software extracting EXIF?

(Sorry, my Matelot Matey, for the long delay in response. This one slipped past me with muffled oars.)

The shutter releases are electrically activated so other than mechanical limits I don't see any reason why the shutter shouldn't be able to adjusted to finer increments than 1/3 stop. The aperture is adjusted by a motor so there is no physical reason why it shouldn't be adjustable in 1/10th stops either.  Of course higher quality mechanical and sensor elements might be needed than are currently in either the camera bodies or lenses so there might be an increased cost.

For most images an accuracy of ±0.15 stop is much more accurate than the built-in metering or chimping, which is what most photographers use.  For most photographers 1/3 stop increments is fine so there just isn't enough reason for the manufactures to give us those capabilities but I for one would welcome 1/10th stop exposure adjustments as an option.

This is one of the reasons, among others, that I rarely use Manual mode exposure setting on my camera, except when using studio type flash.

I'm an old hand so I prefer using both the camera and flash in Manual mode but in the right circumstances I have been known to use aperture priority, E-TTL, and on a very few rare occasions even the P mode of my 7D.

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