Dynax 7Xi - Does it see a black subject , grey %18 ?

[Mustafa Umut Sarac]

For example , We have Black Horse subject, Does Dynax 7Xi shoot it grey % 18 ?

 

[pentaxuser]

Yes, if the meter in the camera only covers the horse and does not take account of anything except the horse's black hide

All meters are designed to record about 18% grey

Was this not covered by the teacher in the class you attend ?

pentaxuser

 

[loccdor]

Yes. Only handheld meters in incident mode work differently.

 

[Mustafa Umut Sarac]

Yes. Only handheld meters in incident mode work differently.

incident meter , what is the other technology , can incident meter be made at home. My friend is working on a diy lightmeter , what is your advise to make it incident meter ?

 

[koraks]

what is your advise to make it incident meter ?

Don't. There are plenty of meters out there that work just fine. Making a meter involves the challenge of making it work well under various circumstances. Companies like Pentax, Seconic, etc. spent millions in R&D to figure out how to do this. Making a meter at home that's even close to the accuracy and dependability of the one inside your Dynax camera is virtually impossible.

The truth is that the meter in your camera is great; you just have to learn to use it.

 

[Paul Howell]

The 7XI has average, matrix and spot metering. In the average mode, if the horse takes up the majority of the frame then you will a gray horse. Average meters assume that any subject is comprised of shades from Zone IX to 1 and averages out all the tones to 18% gray or zone V. In spot mode, what ever you meter spot is seeing will be exposed at zone V. I think the 7X1 it is about 3%, In Matrix metering, maybe, maybe not. If all the cells are reading the same tone, then you will get zone V, but if you are back a bit with some backlit, maybe the chip understand that you have a black object and will compensate for Zone III to I. It is best guess by the chip. Best bet is to use a gray card or the plam of your hand as the referance for you horse shot. Of understand that you are reading in Zone V, underexpose by 2 stops to zone III, the core of the Zone System.

 

[Alan Townsend]

For example , We have Black Horse subject, Does Dynax 7Xi shoot it grey % 18 ?

You can buy lux meters online for about $10 that will work as incident meters. You need to convert lux to EI, then calculate exposure using tables. Phone apps are even cheaper.

 

[RalphLambrecht]

Don't. There are plenty of meters out there that work just fine. Making a meter involves the challenge of making it work well under various circumstances. Companies like Pentax, Seconic, etc. spent millions in R&D to figure out how to do this. Making a meter at home that's even close to the accuracy and dependability of the one inside your Dynax camera is virtually impossible.

The truth is that the meter in your camera is great; you just have to learn to use it.

I made it a point only go to DIY if what I want cannot be bought. Why bother otherwise?

 

[Paul Howell]

You can also use a white foam or other white plastic cup over the 7Xi lens, a zoom set from wide to normal seems to work fine. Use the camera as a incident meter. I used this tech with several cameras, Sony digital, Minolta A mount, and Sigma digital and film. Foam seems to work well, cheap.

 

[loccdor]

In most outdoor conditions learning the extended sunny 16 rules and manual mode are faster than incident or reflective light metering. It's only in certain ranges of conditions (LV12-LV9 mostly) that it's difficult to tell what the light value is with these rules.

 

[koraks]

You can also use a white foam or other white plastic cup over the 7Xi lens, a zoom set from wide to normal seems to work fine. Use the camera as a incident meter. I used this tech with several cameras, Sony digital, Minolta A mount, and Sigma digital and film. Foam seems to work well, cheap.

It does depend on the transmission of the cup, though, making the selection of the cup quite critical.
Also, foam cups may be available where you live, but they're nonexistent here. Same for the thin plastic cups.

 

[wiltw]

It does depend on the transmission of the cup, though, making the selection of the cup quite critical.
Also, foam cups may be available where you live, but they're nonexistent here. Same for the thin plastic cups.

Furthermore, if one is comparing a foam cup to a legitimate incident meter, for selection of the 'best' cup, one should make sure both the cup and the incident meter dome are oriented similarly in space, so as to not be misled...the angle of the incident hemisphere in space DOES make a difference in the reading, which is why the standard instruction is to stand at subject postion and aim the incident dome toward the camera lens, to take an incident reading. Extracted from a prior post of mine, to illustrate the positioning/aiming variability (and also the fallibility of always believing the Sunny 16 rule of thumb applies in sunlignt):

"...will vary the incident meter reading as you rotate horizontally 360 degrees. This taken from one of my own posts years ago...

posted June 23, 2021​

"1. Just now I metered with my handheld Minolta incident meter (ISO 250, 1/250 shutter), held perpendicular to the ground (as if aimed to the camera lens), and as I rotated the meter 360 degrees I detected readings between f/11 +0.1EV to f/11 +0.7EV at 1:30pm on a birght cloudless sky at 38 degrees latitude. So here right now, Sunny 16 would be underexposed by -0.3EV to -0.9EV! Color transparency would do fine, but color neg would be getting into the possibility of 'muddy color' in the shadows.​

2. One hour later, I metered with my handheld Minolta incident meter (ISO 250, 1/250 shutter), held perpendicular to the ground (as if aimed to the camera lens), and as I rotated the meter 360 degrees I detected readings between f/8 +0.6EV to f/11 +0.9EV at 2:30pm on a birght cloudless sky at 38 degrees latitude. Deviation from Sunny 16 got even greater, by -1.4EV at one side, but better at -0.1EV at the other extreme."​

​

And a set of readings taken just now (at 9:15am on a bright clear day) read from f/16 +0.2EV down to f/4 +0.7EV, as I rotated 360 degrees (to mimic the camera taking my own photo from different camera positions)

Another update, laster today at 1:45pm, read from f/16 +0.2EV down to f/8 +0.1EV, as I rotated 360 degrees.

Plus, I got f/16 +0.7EV in July 2022, and posted that on Photrio, with the hemisphere pointed AT the sun.