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Author Topic: Using Spot Metering and Exposure  (Read 10094 times)

BobShaw

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Re: Using Spot Metering and Exposure
« Reply #20 on: February 02, 2017, 07:49:52 PM »

When you spot meter for the highlights you have to add +2 EV which will retain detail in the highlights and the shadows will be lighter, which means less noise if you have lighten the shadows further in your photo editor.
The best answer here by a country mile. Using a reflector is also a good idea.
In short, the highlights are at the right end of the histogram so two stops over the reading taken should ensure they are not blown.

You are probably confusing people with your question as you are asking about spot metering which most will take to mean the Spot metering mode in your camera meter. However you then mention Sekonic so I take it that you are taking an INCIDENT AMBIENT light measurement at the subject using a hand held meter., which is much better anyway.
In either case this is a Photography 101 question and you don't need software to get it right.
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mouse

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Re: Using Spot Metering and Exposure
« Reply #21 on: February 02, 2017, 07:53:24 PM »

The problem you pose is a classic example of a situation which just begs for multiple (maybe only 2) exposures and HDR blending in post processing.  Why are you so adverse to this solution?
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BAB

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Re: Using Spot Metering and Exposure
« Reply #22 on: February 02, 2017, 08:13:41 PM »

You don't need to do HDR which by the way the is easy you should however do exposure blending with luminosity slices or just blend the shawdow with the mid tones and highlights it's also very easy non destructive and produces the best results.
Most interior shots even if you only make one exposure need blending at the very least. But as you can gather from all OP the hardest way to get the best results of an interior shot with mixed lighting, strong highlights especially from sunlight coming through an in filtered window is with one exposure your creating a monumental amount of post work.


At this point I would suggest you search you tube there are a few great videos on how to do, also luminosity blending interior shots.


Many pros shoot ten images filling in or highlighting certain important features or areas the your camera no matter what exposure you choose won't be lit right. And yes using gels, shoring the interior during the day and then not moving the camera and waiting four hours for the right ambient light to make the outdoor shot thru the window is all part of the job!


Sorry
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BrownBear

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Re: Using Spot Metering and Exposure
« Reply #23 on: February 03, 2017, 09:11:50 AM »

Some interesting techniques using GELS!! that I had not thought off :-)

Moving the furniture around to suite the style I am looking for is always an option.

Thanks


Our manta for commercial shooting was pretty straight forward:

"Computer time is unpaid. Better to shoot it right in the first place and move on to the next paycheck."
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BobShaw

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Re: Using Spot Metering and Exposure
« Reply #24 on: February 03, 2017, 06:34:34 PM »

The problem you pose is a classic example of a situation which just begs for multiple (maybe only 2) exposures and HDR blending in post processing.  Why are you so adverse to this solution?
There are only 6 stops of range. Any camera made this decade should do that.
The question was about selecting exposure.
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KMRennie

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Re: Using Spot Metering and Exposure
« Reply #25 on: February 05, 2017, 11:36:51 AM »

I have a Sekonic L758DR and a Nikon D810. Having calibrated the meter to the camera I would spot meter the brightest point and open up by 3.5 stops. This gives me a file where the brightest points are just below clipping verified using RawDigger. From your measurements 6 stops below brightest should still be fairly noise free. Without calibrating the meter to the camera and using RawDigger or similar you are unlikely to arrive at an exposure that is just below clipping without a great deal of trial and error or a bit of luck. To answer which exposure, for me it would be the one that preserves the highlights. A bit of fill, either with a reflector or a bit of flash may give you a nicer looking file without PP but I would be surprised if you couldn't get a nice file with a proper ETTR exposure. Hope this helps. Ken
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BobShaw

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Re: Using Spot Metering and Exposure
« Reply #26 on: February 05, 2017, 09:30:19 PM »

I have a Sekonic L758DR and a Nikon D810. Having calibrated the meter to the camera
Why. One is an incident meter and one is a reflected meter.
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Martin Kristiansen

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Re: Using Spot Metering and Exposure
« Reply #27 on: February 06, 2017, 05:57:51 AM »

Why. One is an incident meter and one is a reflected meter.

I am pretty sure the Sekonic is a dual incident and reflectance meter.  I have an older Sekonic and it seems much the same as the one quoted here.

I am not understanding the backwards and forwards on this thread. It's very simple. If you are using the 1 degree spot measure the brightest area that is causing all the concern. Measure the darkest area you want to retain some detail. How many stops difference do you have. If it is 6 stops I don't see a problem. If it is substantially more shoot an extra frame either a darker one to hold the highlights or a lighter one to hold the shadows. Many ways to combine in post.

Personally I would take an incident reading to give me an average exposure and then measure the highlights and see how many stops over it was. Three or less I would shoot the incident reading. Much more I would close down one stop and two stops using either shutter speed or ISO. It's not common to combine incident and reflective readings to build up a picture of the scene but we used to do it in film days on occasion. Easier than hunting that midddle grey if you didn't have a grey card.
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KMRennie

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Re: Using Spot Metering and Exposure
« Reply #28 on: February 06, 2017, 10:46:30 AM »

The L758DR  has both spot and incident meters. In this instance I would only use the spot meter but everyone to their own. Ken
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BobShaw

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Re: Using Spot Metering and Exposure
« Reply #29 on: February 06, 2017, 04:50:21 PM »

Incident is measured at the subject position of light hitting the subject. It does not depend on the colour of the subject and is therefore accurate.
Reflected is measured at the camera position of light reflected from the subject. The reading therefore varies depending on the colour of the subject as well as the light hitting it.
It may be possible to take an incident reading at the camera or a reflected reading at the subject, but neither would be correct as the collection area is different.
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BrownBear

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Re: Using Spot Metering and Exposure
« Reply #30 on: February 06, 2017, 08:53:54 PM »

We still have several Sekonic L758DR and more of its predecessors dating back over the decades. It's most definitely both a spot and incident meter. Because we used a lot of fill light balanced with ambient, I can count on one hand the number of times I used the spot meter indoors as proposed by the OP in this thread.

The combo of incident and spot makes for a whale of a light meter, saving us a whole lot of time onsite and on the computer, making money for us all the while. When you're gelling strobes as well as adjusting balance with ambient, they're priceless. 
« Last Edit: February 07, 2017, 04:05:37 AM by BrownBear »
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SZRitter

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Re: Using Spot Metering and Exposure
« Reply #31 on: February 07, 2017, 09:11:19 AM »

I wish they hadn't stopped the production of the 558R (I think that is the right number). I have one, which is also incident and spot meter, and it is amazing in situations where you want to see individual values. I would get a 758, but they seem insanely expensive compared to what the 558R retailed for.  :'(

To the OP: You should do a bit of homework with the spot meter and your camera(s). Personally, I would find something, with a bit of detail, and a bit of color. Spot meter that (so it's middle gray), then take exposures adjusting your camera one stop at a time until it's blown out. count the distance in stops between the initial reading and the last spot you preserved detail to your liking, and then when you are in the field, you'll have an idea of what you can expose for and retain highlights. Basically, you found (and I may have the number wrong) Zone 0 for your camera.
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stamper

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Re: Using Spot Metering and Exposure
« Reply #32 on: February 07, 2017, 09:48:29 AM »

I have been into photography for 15 years and I have never seen anyone using one. I was under the impression that they have little relevance to digital photography. Obviously some enjoy using one of them but are they really useful?

BrownBear

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Re: Using Spot Metering and Exposure
« Reply #33 on: February 07, 2017, 11:12:28 AM »

Obviously some enjoy using one of them but are they really useful?

Priceless in the settings I described. If you don't have one when adjusting lighting ratios and balancing lights and light sources for indoor shooting, might as well take up golf. The OP is trying to set up an indoor shot.
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BrownBear

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Re: Using Spot Metering and Exposure
« Reply #34 on: February 11, 2017, 09:42:44 AM »

BTW-

If you want your mind thoroughly blown on lighting (and the use of incident meters), both natural and artificial as well as their mix, zero in on the teachings of the late Dean Collins.  I know of NO ONE before or since who understood and used light, subject form, tonality and texture so well.  I had the good fortune to work with him a couple of times, as well as attend a couple of lectures and a 2-day workshop.  All these years later my mind still reels at his brilliance.  Best place to start is with his DVD's, most notably this set. Watch #4 first, or he'll submerge you like a tidal wave with all the info in the others. Here is a good review at Strobist.
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Doug Gray

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Re: Using Spot Metering and Exposure
« Reply #35 on: March 26, 2017, 02:27:21 PM »

dear, you need to use tools that can show clipping in raw - rawdigger, fastrawviewer or converters that can do the same like rawtherapee or rpp

^This is good advice. There is a great deal of margin built in to digital cameras. It's there to allow compression at the high tone end to simulate film. Digital cameras get better and better as the exposure increases - until they clip, then it's a hard clip. Very unlike film. These tools let you characterize it and know what you can get away with.

You can also experiment by taking various overexposures and dropping the exposure slider up to 3 or 4 ev or so in the RAW conversion. If the sensors are hard clipping you will see that happening and won't be able to recover dropping the slider any further.
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Jim Metzger

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Re: Using Spot Metering and Exposure
« Reply #36 on: March 30, 2017, 10:10:35 AM »

I would also like to know from the OP if you are using base ISO. The DR of the sensor drops as you increase ISO and makes it more difficult to extract all the info.

I would also look at noise reduction in just the shadow areas. What is your intended output? Small reproductions for web and actual prints tend to show much smoother output than zooming in to 100% or more of the RAW image at the computer.

I also recommend calibrating your camera with a Colorchecker Passport and making sure you get the white balance right (or at least close) in camera. My experience is the more you manipulate the file, even RAW, the less "headroom" you have to work with.
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Doug Gray

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Re: Using Spot Metering and Exposure
« Reply #37 on: April 02, 2017, 01:21:01 PM »

Know your camera and shoot RAW. If the scene has a wide dynamic range set exposure using spot and add enough EVs to maximize light collection without sensor clipping. This is fast and isn't hard to do with a bit of initial experimentation on any new camera.
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uuglypher

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Re: Using Spot Metering and Exposure
« Reply #38 on: May 25, 2017, 07:53:27 PM »

Several responders have approached this alternative using the full capabilities of raw image data capture.

If you have determined how much raw-accessible dynamic range your camera has beyond the point at which the jpeg histogram frame indicates clipping (varies camera-to-camera, but usually is between one and three full stops of extra raw-accessible DR (ERADR)  you may easily be able to avoid HDR.

Using the sensor's full available raw dynamic range, simply expose for the brightest possible image without clipping highlights, but coming as close to doing so as possible. The thumbnails will appear badly overexposed (as they WOULD be if they were jpegs) but in your raw converter will be easily tonally normalized by moving the Exposure slider to the left. A win:win technique: capture the absolute least possible noise, image data of the highest possible Signal-to-Noise ratio, and capture image data with the greatest potential breadth of creative and artistic interpretation...from high key to low key, and every variation in between.   Every brightness level in the scene is captured with the highest number of photons possible...from the brightest highlight detail to the darkest of shadow details, and delivers the maximum tonal and color spectra permitted by the bit depth of image file.

Some call it a "digital negative" but it is much, much more than that. It is analogous to an unlimited collection of unprocessed latent images.

It's a real shame the camera manufacturers don't provide an in camera raw histogram! But there surely would be a prohibitive per-unit cost, given the variation in ERADR that occurs from sensor to sensor. So it's up to you to determine, by test exposures, the actual raw-accessible DR of your camera.

But give it a go: it's well worth the effort!
You'll  like it.

Best regards,

Dave


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uuglypher

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Re: Using Spot Metering and Exposure
« Reply #39 on: May 27, 2017, 12:03:52 AM »

scyth
blagojevic
SZRitter
pegelli
KMRennie (mentions ETTR
Doug Gray
Jim Metzger..( mentions loss of DR with incr ISO)

Above are seven responders to the OP who indicate awareness of the "headroom" that digital camera sensors provide that  can be  "useful for recovery of some cases of blown highlight detail".

The remarkable aspect of "headroom" is that, even among cameras of the same make and model, that headroom can vary.  Three cameras of the same brand and model were tested: one had an extra  2/3 stop, the next one and 1/3 stops, and the third  had two and 2/3 stops of extra DR ....  indicating that each and every camera ought be tested for its actual raw-accessible DR.!

If any of the responders above have done such testing of their own camera to determine how much extra raw-accessible DR it has beyond the point that the JPEG clipping warning /blinkies is set off, I'm hoping they would report their results at base ISO. 

The loss of DR with increasing ISO is extremely variable. I have one camera with extra DR of one and 1/3 stops at ISO 100 that loses its first 1/3 stop at ISO 400, and another with one and 1/3 stop at ISO 100 that waits until ISO 1600 before it loses its first 1/3 stop of DR.

y'gotta test your camera!

Dave
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