Film speed test

[yya]

I drew a diagram to express my idea, but I’m not sure if there’s a difference between the two approaches or which one is better.

 

[Chuck_P]

Well, in black and white film testing it would be diagram #1..........nice even shade on the test target, camera would be much closer to the target. I've never done color testing.

 

[yya]

Well, in black and white film testing it would be diagram #1..........nice even shade on the test target, camera would be much closer to the target. I've never done color testing.

Could you please have look both attachment, one is from Alex test film speed document and another one is from pictorial on YouTube

 

[yya]

Well, in black and white film testing it would be diagram #1..........nice even shade on the test target, camera would be much closer to the target. I've never done color testing.

 

[Chuck_P]

The main idea is that the target should not have any shadows cast on it, even the slightest bit of shadowing so that it is evenly lit across it's surface. A cloudless day ensures that the intensity of the light on the target doesn't change as it would if a cloud moved in front of the sun at the moment before you release the shutter. A consistent overcast wintery day when the clouds are heavy works just as well imo, as it provides even diffuse lighting on the target, as long as the overcast is heavy so to speak and not a thin overcast sky, where any movement of the clouds may more easily change the intensity of lighting on the target. I suspect in Australia, you don't have to wait long for a sunny cloudless day.

 

[yya]

The main idea is that the target should not have any shadows cast on it, even the slightest bit of shadowing so that it is evenly lit across it's surface. A cloudless day ensures that the intensity of the light on the target doesn't change as it would if a cloud moved in front of the sun at the moment before you release the shutter. A consistent overcast wintery day when the clouds are heavy works just as well imo, as it provides even diffuse lighting on the target, as long as the overcast is heavy so to speak and not a thin overcast sky. where any movement of the clouds may more easily change the intensity of lighting on the target. I suspect in Australia, you don't have to wait long for a sunny cloudless day.

Thanks so much!
Now I think I understand why some people recommend a completely clear sunny day or a heavily overcast cloudy day!