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Sekonic L-758D
- Thread starter CJVW
- Start date
You can download the full manual here :
http://www.sekonic.com/products/l-758d/documentation.aspx
Page 17 is probably what you want.
http://www.sekonic.com/products/l-758d/documentation.aspx
Page 17 is probably what you want.
Thanks for your reply darklamp, I have downloaded the pdf, I also have the full instruction book, the only reference to the number after the set aperture, is an arrow pointing to it, named a tenth of the shutter speed, but this does not correlate with the given shutter speed. sorry if I sound stupid but I have only used simple light meters in the past, this is my first actual venture into medium format film photography,
tclune
Senior Member
To understand this, you need to understand a few things about your camera's aperture. First, lens apertures are referred to as "stops." Full stops are 1/1.4, 1/2.0, 1/2.8, 1/4, 1/5.6, 1/8, 1/11, 1/16, 1/22, and 1/32. (You could keep going in either direction, but these are the ones you are likely to see.) Now, the 1/1.4 stop lets in twice as much light as the 1/2.0 setting for a given shutter speed; 1/2.0 gives twice the light of 1/2.8, etc. [A couple of asides: First, you will usually see the numbers given as just the denominator, but this is a source of confusion -- the aperture gets smaller as you move from left to right in the list: if you show the true numbers, which are fractions or ratios, you can see that the numbers are getting smaller, too. Second, the numbers are ratios relating to the diameter of the opening. If you square them, you get 1/2, 1/4, 1/8, etc. So you can see the change in area reflects the actual change in amount of light, a fact obscured by using the diameter instead of the area of the aperture.]
Now, light meters can measure light more accurately than the factors of two represented in these full stops -- and your camera can set apertures that are in finer increments than that, too. As it happens, cameras typically allow you to choose either half-stop increments or third-stop increments. So the light meter manufacturers have traditionally reported the light setting in increments finer than either of these possibilities. If the light meter says the right aperture is 2.8.3, and you were using third-stop increments, you would choose the stop one smaller than 1/2.8, or 1/3.2. If you use half-stop increments, you would presumably still go one half-stop smaller than 1/2.8, although there is obviously some slop in the mapping between the tenth-stop measurements and either third or half stop increments. As you get comfortable with your equipment, you will learn what step to make for which mapping -- but, for the most part, it isn't very critical. Set the aperture to either side of the light meter reading and you'll be fine. FWIW
Now, light meters can measure light more accurately than the factors of two represented in these full stops -- and your camera can set apertures that are in finer increments than that, too. As it happens, cameras typically allow you to choose either half-stop increments or third-stop increments. So the light meter manufacturers have traditionally reported the light setting in increments finer than either of these possibilities. If the light meter says the right aperture is 2.8.3, and you were using third-stop increments, you would choose the stop one smaller than 1/2.8, or 1/3.2. If you use half-stop increments, you would presumably still go one half-stop smaller than 1/2.8, although there is obviously some slop in the mapping between the tenth-stop measurements and either third or half stop increments. As you get comfortable with your equipment, you will learn what step to make for which mapping -- but, for the most part, it isn't very critical. Set the aperture to either side of the light meter reading and you'll be fine. FWIW
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Thank you tclune, I understand the F stop settings re the lens on the camera and the increments in between the F stops, what I don't understand about the sekonic L-758 light meter is that when set to aperture priority and I have set the aperture to the desired F stop setting to suite the depth of field I require, why is the meter giving me an adjustment of the aperture at all, why is not just giving me the correct shutter speed, The instruction manual for the sekonic says that the numeral to the right of the aperture value is one tenth of the shutter speed, and even this doesn't actually correlate to the meters selected shutter speed displayed on the left, Thanks again to anyone who can help me, I am fairly experienced with photography from back in the 35mm film days, its just the Sekonic meter I have to come to grips with.
chris102
Senior Member
... shows how to use exposure compensation and p41 shows filter compensation in 1/10 of an f/stop increments. This is not the 'tenths' place in a decimal number like f/5.6, but tenths of a full f-stop. This number is used when applying compensation to a reading, and should be zero when using the meter in simple aperture mode.
I've used this meter often, and hate it because of its complexity. However when doing multiple light shooting, the obscure features come in handy. But only if it has been carefully calibrated first.
Thanks for the reply, so does this numeral to the right of the selected aperture when measuring in aperture priority, which is described in the instruction manual as I/10th of the shutter speed, mean you then have to adjust the camera lens by 30% of an F stop if say the numeral is 3, I have read the instruction manual from top to bottom and find this is the only thing that bewilders me, I only bought the meter in the first place because it looked good for taking accurate spot readings through the viewing lens, Thanks again. Chris.
The small number to he right is the fractional part of an f stop. For example a large 16 followed by a small 7 is simply f16.7.
The Lightmeter measure is tenth stop increments but the aperture scale isn't linear so 7 tenths of one stop isn't 0.7 its a logarithm so i gues thats why they don't use a decimal point.
Most cameras can only set in1/3rd stop increments so you need to select the closest value. In this case (assuming 1/3rd stop increments) You would set the aperture 2 clicks down from f16 or 1 click up from f22. At least that's what the measured value on the lightmeter is reading.
Hope that helps
Regards
John
tclune
Senior Member
I may not understand the nature of your confusion, but let me try again. Shutter speed can be changed to cut the amount of light hitting the sensor just like aperture can. If you have the camera set to f/2.8 and 1/100 sec shutter speed, you can stop down a full stop by setting the aperture to f/4 or by setting the shutter speed to 1/200 (or some combination of those settings.) Of course, you could also slow the ISO by half if you so desired. All of these changes are equivalent in terms of the amount of light the sensor will record. So, if the light meter says you need to set the aperture to f/2.8.6, you could leave the f-stop right where it is and adjust the shutter speed to 1/160 sec (do two clicks faster on the shutter speed instead of two clicks smaller on the aperture -- they have the same effect on exposure. So there is no need to report the fine increment in more than one place -- there is a simple equivalence between these settings. HTH
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Thanks for your reply John, I'm beginning to understand that the numeral to the right of the selected aperture is a percentage of an F stop, displayed in one tenths. it just seems strange to me that when metering in aperture priority it then gives me an adjustment to make to the aperture of the lens rather than an adjustment of a partial stop with the shutter speed, especially as the L-758D instruction manual calls the numeral 1/10th shutter speed when in aperture priority mode. Thanks for every body's replies. Chris.
Chris
Try asking any questions about your light meter in the Studio & Lighting forum. There are some very helpful and knowledgeable people there who will be glad to help.
Regards
John
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