# Sekonic Speedmaster L-858D

3 replies to this topic

### #1 Kenny Keeler

Kenny Keeler
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Posted 20 July 2017 - 04:43 PM

Hey all,

I wanted to start a discussion about Sekonics new L-858D meter with the spot meter.

Has anyone used this and if so how do you like it. I have the Sekonic L-478D and love it but want to switch for the 858D.

My biggest curiosity is with spot meter. in the specs it says it has 1 degree spot meter. Sekonics older  L-758  has 1 degree 5 degree and 10 degree capability.

Say I want my background at a certain level for this example I will say 2 stops under key. If I use the L 858D which gives me a 1 degree spot reading how small of an area is this measure? I know it is probably based on the distance from the subject I am trying to measure. my question with 1 degree is this a valid spot meter that can get me through most situations spot metering walls, green screens, windows etc.

Also curious of examples of when the 5 degree and 10 degree come in handy.

Thanks!

Sekonic L-858D

Sekonic L-758Cine

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### #2 Gregg MacPherson

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Posted 20 July 2017 - 06:19 PM

Kenny, if you remember your high school math you can calculate the width of the spot.  O/A=Tan.   Where O is the spot width,  A is the distance from the meter,  Tan is the tangent of the spot angle.  So O=A x Tangent of the spot angle.

At a distance of 10'....

Tan of 1deg is 0.0175,  means a spot 2" wide...

Tan of 5deg is 0.0875,  means a spot 10" wide...

Tan of 10deg is 0.176,  means a spot 20" wide....

The wider spot angles are maybe useful for averaging uneven values,  but with one degree you can just see the range of values and average them intuitively.  If I only had one angle it would be 1deg.

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### #3 Reggie A Brown

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Posted 23 July 2017 - 05:24 PM

I use the L858d. I like it. You're aware that the size of the spot is based on the distance from the subject/surface, so I don't know what your real question is. The spot meter shows the light reflected off a surface, so depending on the subject/surface I'm not sure I'd want to use a spot meter cause you'll get a different reading from different areas, even with even lighting.

Example: If you have a 6'x6' black and white picture on the wall, the black paint on that picture will show a different reading compared to the white paint on that same picture with the same amount of light illumination hitting the whole picture evenly. The black paint will soak up more light, while the white will reflect it more.

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### #4 Gregg MacPherson

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Posted 23 July 2017 - 06:20 PM

The reason to use the spot meter is to see the relationship between all those different values of light and dark.  I used to carry a folded 2" card with black, white, 18" grey on it.  So you could normalize your eye occasionally,  reading that.  The 18% grey reading should be almost identical to what an incident reading will give.

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