Flash Meter reading blows highlights

[jeremy_wakefield]

<p>I have a meter which I use for setting up studio lights and particularly getting ratios fixed. However recently I've started using Speedlites a lot more ( age and portability issues ) and had some great results using them both on and off camera. I've just eyeballed it and adjusted as required if in manual mode. In ETTL I use a quick flick of the FEC to get what I want.</p>

<p>Anyway, I decided it would be interesting to use my meter to get a quick and more accurate starting point, so I gave it a go. What I found is that using the meter setting I had a fair number of the lighter coloured areas blown and I needed to adjust accordingly.</p>

<p>I was using the speed light near to the subject and I assumed it was the inverse Square law and increased contrast at work ( though I had assumed the meter would take care of this). However, I then noticed that photographing something in front of a light background meant the background sometimes was blown so it can't be that. </p>

<p>I'm not sure what I'm doing wrong here so if you can help please do. It would be much appreciated.</p>

<p>Thanks</p>

 

[Matt Laur]

<p>Is your meter picking up on a pre-exposure metering or remote control flash? If so, that pre-exposure pulse (or pulses) is much weaker than the during-exposure flash output, and having the meter fooled by it would definitely result (if you take the meter's advice) in an over-exposed shot.</p>

[jeremy_wakefield]

<p>I'm using the flash in manual mode though not ETTL. It isn't grotesquely overexposed just some of the highlights seem to be over</p>

 

[ellis_vener_photography]

It would be good to see examples. Also how are you using the flash meter? And which triggering method are you using?

[jeremy_wakefield]

<p>Hi again.</p>

<p>Hmm. Humble pie time I'm afraid.</p>

<p>I've just got home and had a proper look on my computer. When I look at the RAW file in LR there are only a very small number of overexposed highlights showing as clipped and they can mostly be recovered. It seems that it is the blinkies on my camera LCD that is suggesting that these highlights are significantly blown. They also looked blown on the camera histogram. I knew that these aren't 100% a reliable means of checking but it looked really blown out. </p>

<p>Normally if shooting at an event, I use the blinkies for exposure checking. I knew there was a margin for safety but there's obviously a lot more latitude than I thought. Just goes to show you. I don't recall having this safety net with my 5D mk 1. Do you know if the blinky safety zone varied from individual camera copy to copy or just from model to model?</p>

<p>Anyway, seems that the subject was just pretty contrasty and the jpeg preview was too much for it. If I use one of the camera calibration presets in LR it blows them again.</p>

<p>Sorry folks. My mistake but thank you for your help and comments</p>

[colin_mattson1]

<p>As Ellis said, examples would definitely help.</p>

<p>If you're using bare Speedlites, the thought that immediately comes to mind is that they can present a much smaller target to meter. Particularly if you're cranking up the head zoom, it's definitely possible to pop off a reading outside the "hit zone" and end up hotter overall than you intended.</p>

<p>The zoom optics on some models also hotspot in a gnarly way, but if you're using a consistent lighting setup, the pattern would probably pop out at you if that were the issue.</p>

<p><strong>Edited to Add: </strong>The blinkies vary from model to model and firmware to firmware, but more to the point, they vary with your JPEG settings. If you want fewer blinkies, turning down the contrast (because the defaults are pretty punchy) or trying a different Picture Style (and then again adjusting the contrast as needed) is an excellent start. Canon's "Neutral" style will blink a lot less than the consumer-friendly "Standard."</p>

<p>Personally, I have the Technicolor CineStyle profile installed and use that for everything. It gives me a good idea what I've actually got—at the cost of being <em>extremely</em> flat and desaturated if I need to show a client something on the back of the camera.</p>

[jeremy_wakefield]

<p>Thank you Colin. Some good information there. I was using bare speedlites so you're probably right and that combined with the jpeg rendering on my LCD is the answer to my issue.</p>

<p>I haven't tried the profile you mention and I might give it a go. Thanks for the suggestion</p>

[rodeo_joe1]

<p>This sounds more like a subject failure problem than one of metering. You have to remember that specular reflections from shiny surfaces will get 'seen' by a TTL metering system, but not by a lightmeter.</p>

<p>How are you metering? If you're measuring the lights individually to get a ratio, and then using the most powerful light to meter the exposure, then you <em>will</em> get overexposure, since light is additive and any fill light will add to the key. Set your ratios and then do an overall incident reading from the subject position, pointing the meter dome back at the camera position. Always remembering that an incident reading is meant to give a correct exposure to non-shiny subjects - i.e. matt surfaced objects.</p>

<blockquote>

<p>"Do you know if the blinky safety zone varied from individual camera copy to copy or just from model to model?"</p>

</blockquote>

<p>It varies from make to make and model to model. My old Canon 5D had about one stop of headroom. My Nikon D800 has at least one-and-a-half stops. But this shouldn't be used except as insurance, since it's possible that saturated colours will become distorted if their exposure is taken too close to the limit.</p>

[ellis_vener_photography]

To follow up on what Colin said about the preview. Both the histogram and preview (including overexposure blinkers) are

base.d on the camera's JPEG processing settings. To get a closer indication of what the raw data actually looks like,

switch the camera from sRGB to Adobe RGB(1998) and choose camera neutral or flat as the picture style. If you have the

option turn saturation down a touch as well.

 

If you have a deeper interest in histograms and why you shouldn't fullybtrust what yousee on the camera's preview display: http://www.ppmag.com/web-exclusives/2007/12/what-is-a-histogram-and-how-do.html

[jeremy_wakefield]

<p>Thanks Ellis. I will make the necessary adjustments. Although I knew about the JPEG situation in the LCDD, I don't usually find the blinkies to be unreliable but in this case the contrast and nature of the light obviously did expose the shortfalls. I will have a look at your article. Thanks.</p>

<p>Hi Joe. Yes I get that about the light ratios cumulative effect and I'm pretty good with studio settings. i reckon it's the LCD characteristics for which I hadn't made sufficient allowances</p>