E510 exposure problems.

[DiGdUb]

Tried shooting tonight outdoors at orchard. I found out that when set to the esp matrix metering mode, shots tend to turn out underexposed. Centre weighted metering seems better, but still is unreliable, sometimes under exposed and sometimes overexposed. Anyone has such issues? And how to improve it? Thanks.

[Kirika]

Well...if your camera's constantly underexposing by a fixed amount, simply dial in that fixed amount to compensate? An alternative would be to use longer exposures and a tripod.

[OlyFlyer]

No, if it systematically under or overexposes than there is something wrong with the camera, or something wrong with the way you take the images. Try to take several test images under similar, or preferably the same conditions to see if the behavoir is systematic. Post some images, that would make it easier for us to help. Maybe just something simple, like you use the wrong priority mode, or something similar. Use raw for the test, convert to jpeg afterwards in computer.

[headfonz]

there are 2 ESP metering modes, try changing it to ESP (independent from AF) and it will be more accurate. the ESP + AF mode tends to under / over meter from my experience.

[drakon09]

Better to post the images so we can visualize what you're saying.

[DiGdUb]

thanks for the tip, headfonz. i will try it out.

here's a pic which i think is underexposed.


sorry, i have deleted the pics which i think were overexposed or underexposed. but the feeling i get the camera is trying too hard to keep highlights from being blown, which results in underexposure, or keeping shadow from being clipped, which result in overblown pictures.

[drakon09]

The exposure looks fine to me.

[microcosm]

You can easily bring out the shadow details from the image. The problem with night shooting (I have been doing tons of this lately) is learning how to balance out the dark and light areas in your image composition. And take care with the blowing of the bright areas. You can also use layer merging in Photoshop to bring out the dark areas. Not very hard.

[DiGdUb]

Thanks. I will experiment more with the exposure on this camera. Maybe the pic i posted is ok, but some shots i deleted were quite bad. For eg, i was trying to shoot the national museum and the museum came out like a white hot glowing block because the camera had tried to expose for the dark sky behind the museum. When i was shooting the christmas lights on orchard road, the camera tried to meter for the lights, and resulted in the roads and nearby buildings looking very dark. This is quite erratic and i think no amount of post processing can fix. I will try more shots and maybe learn how this camera does its metering.

[headfonz]

hmm, if your metering mode is on ESP + AF, the camera may try to even out the metering relative to your AF point. so in the examples you mentioned, it probably can't compensate enough for the high contrast scenes since the NMOS sensor isn't famous for its high DR.

[OlyFlyer]

I think the shot you show is very difficult for the camera to take it better, because there is the very large unlit area to the right and the top left part. If I would have taken the image I would have moved forward to exclude at lest the right side with tha wall.

Here are some similar images, taken in Brussels, indoor using available light. I had to adjust WB manually and I think I added +0.3 EV to all of them as well.

#1


#2


#3


Especially, #1 and #2 needed some work on, but I think they turned out acceptable. I don't really like #3 as much as the first two. None of them are taken point and shoot style, I usually spend some time thinking, waiting and moving around before pressing the shutter release. Try always to visualise what gets in the field of view before taking the image, check after taking the image what went wrong, and try to take from a different angle until you understand how different things effect the final image. Some images are not possible to get right without post processing, and as others say as well, it is usually better to undreexpose than to overexpose, as most of the time recovering highlights is practically impossible.

By the way, here is #4, showing the light which was available. Actually, glass roof, but heavily overcast sky, really dark. This image needed some pp work as well.

[microcosm]

Typical humans see their world in 16 f-stops, or measurements of light reflecting off their environment. Cameras see no more than 5 stops at once. So the more contrast there is in the scene, the more stops of light there are to BE seen. This concept means that correct exposure on your camera is critical to avoiding under- or over-exposure. To understand how a camera measures this light, lets start with the proper definitions of Exposure and Metering.

Exposure
Exposure is the quantity of light allowed to act on a photographic material. It is a product of the intensity, which is controlled by the lens opening (aperture), and the duration (shutter speed) of light striking the film or paper. Your ISO setting, your aperture size, and your shutter speed directly impact the exposure of an image.

Metering
Metering is the process of calculating the best exposure from the existing light conditions.

When your digital camera meters a scene, it measures the amount of light in the scene and calculates the best-fit exposure value based on the metering mode (see below for details). All meters are designed to produce midtone results - neither black nor white, neither light nor dark, but somewhere in between. Metering systems are typically calibrated to a value of 18% gray because a typical scene reflects the same amount of light as this gray value. As a result, scenes with high contrast can give the automatic exposure a difficult time.

The metering mode on your camera defines which information in the scene is used to calculate the exposure value. Metering modes depend on the camera and the brand, but are mostly variations of the following three types:

1) Spot (Partial) Metering
Spot metering is a method of metering that only uses a small spot in the centre of the composed scene. The size of the spot varies with the brand of camera, but typically ranges from 1% to 3.5% of the image area. Partial metering covers about 9.5%. Spot metering allows you to meter the subject in the center of the frame (or on some cameras at the selected AF point). This type of metering is useful for brightly backlit, macro, and moon shots. Use this metering method when your scene has significant differences in brightness (e.g. between foreground and background) or for subjects that require precise measurement, such as close-up photography.

2) Center-weighted Average Metering
Center-weighted metering is averaged over the entire scene with emphasis placed on the center area (typically 75% based on lighting conditions at the center and 25% outside). It assumes that you will be composing with the subject in the middle of the frame and most of us know this is not always the case. Center-weighted metering is probably the most common metering method implemented in nearly every digital camera and the default for those digital cameras which dont offer metering mode selection. Most centre weighted systems have greater sensitivity in the bottom half of the frame, which, when used in landscape format, cut down the influence of the bright sky on the exposure. Be careful when using this mode for portrait photography when the camera is turned on its side.

3) Matrix or Evaluative Metering
Matrix was introduced to the world in 1988 with the Nikon F4. This is probably the most complex metering mode, offering the best exposure in most circumstances. Essentially, the scene is split up into a matrix of 3 to 16 or more, typically 6 metering zones which are evaluated individually, taking into account such factors as the focusing point in use, subject size, position, distance, overall lighting level, front and back lighting and color. The overall exposure is based on an algorithm specific to that camera, the details of which are closely guarded by the manufacturer. Often they are based on comparing the measurements to an on-board database of images. Matrix metering uses a microchip that has been exposed to literally thousands of picture-taking situations. As you point the camera towards your subject, matrix metering recognizes its light/dark pattern and reads the light accordingly.

If you test your spot meter on various parts of a scene you've composed, you'll no doubt prove to yourself that there is a vast range of light and shadow, but since the film or digital card cannot record more than a five stop range, what difference does it make? You will still end up keeping the same two or three exposures that were created using center-weighted or matrix metering.

Both center-weighted and matrix metering prove accurate in 90% of ones picture taking efforts. That should boost your confidence in choosing them when you realize that nine out of ten pictures will be a correct exposure! In either center-weighted or matrix metering modes, you can aim, meter, compose, and shoot when your subject is frontlit, sidelit or under an overcast sky.

[microcosm]

Your problem, as you can read above my post above, is not the camera or its metering system.

It is how you use your camera for metering and composition. In cases where you face difficult lighting conditions, you should swap to SPOT or CENTRE WEIGHTED metering and learn to use the AEL (Exposure Lock) button more. That button is my best friend, always.

Shoot on 18% gray cards and if that exposure is wrong, then you have a camera problem. Or else, there is no problem at all.

Hope the above article can help you understand better what you are facing. I shoot a lot of pictures under theatrical lighting and anyone will tell you, it can be a bloody nightmare. Practise makes perfect. Keep shooting.

Pick up a book at Basheer or something, to understand metering and lighting and you will see your nightshoots improving.

[OlyFlyer]

Very well explained. It should be read by everyone, at least every new owner of an Oly camera. Shold be a sticky, at least your tutorial post.

[microcosm]

Originally Posted by OlyFlyer Very well explained. It should be read by everyone, at least every new owner of an Oly camera. Shold be a sticky, at least your tutorial post.

Thanks OlyFlyer.

One thing to add... about Evaluative metering... Olympus's ESP metering is really one of a kind and very accurate these days, and contrary to what has been said above, ESP metering linked to AF is such a powerful feature once you have a good understanding on how to use it. Something that everyone should learn to use as it is an affective implementation to superb metering results.

This might be something we can discuss when I meet you guys again for the Feb kopi session. Please remind me ok? I am getting old liao... sometimes these things slip my absent minded mind...

[OlyFlyer]

Originally Posted by microcosm ... and contrary to what has been said above, ESP metering linked to AF is such a powerful feature once you have a good understanding on how to use it. Something that everyone should learn to use as it is an affective implementation to superb metering results.

I agree, ESP + AF is the one I use very often, maybe most often.

[headfonz]

Originally Posted by microcosm Thanks OlyFlyer. One thing to add... about Evaluative metering... Olympus's ESP metering is really one of a kind and very accurate these days, and contrary to what has been said above, ESP metering linked to AF is such a powerful feature once you have a good understanding on how to use it. Something that everyone should learn to use as it is an affective implementation to superb metering results. This might be something we can discuss when I meet you guys again for the Feb kopi session. Please remind me ok? I am getting old liao... sometimes these things slip my absent minded mind...

looking forward to it then bro

[DiGdUb]

thanks for the explanation. maybe i have to explore the e510's metering system more. currently i have to adjust the exposure compensation anything from to +0.7 to +2 to prevent underexposed pictures. i used nikon d40x and other pns before, and the exposure were usually ok and predictable. with the e510, the exposure is quite unpredictable and sometimes varies wildly between scenes. sometimes, a scene appears underexposed, even though there is a lot of allowance before clipping.

eg. this is at exposure 0.


+0.7 exposure compensation.

[microcosm]

Image (1) The exposure is correct as it is the right exposure for you to push in post production (ie, in Photoshop or some other software) and you can then decide if you want the exposure punchy or laid back. The exposure is therefore "post processing ready" and ask anyone in serious colour correction work and they will tell you they are happier getting exposures like that.

Image (2) If you want to use the jpgs straight out of camera, in cases like events photography, then setting the camera at EV+0.7, Contrast +1, Saturation +2, Sharpness +1 will be good for this purpose as you might not have time to do much post processing work, but you will risk some blown highlights (which honestly, in events shooting, your clients will hardly notice). Then this is the setting you should use.

This is what I feel about the new ESP metering. In the past, the ESP reading was +0.7EV brighter, but the Kodak CCD has better Dynamic Range... still I had a couple of blown highlights I could not save and had to meter correctly and accurately. Hope this helps.

ps: If you didn't know, in Digital Film (HD), the shoot is typically done at -1.0EV. And then pushed up in post as according to one of the top Colour Correctionist in Hong Kong. This is why I applaud the move from Olympus to tweak the ESP reading. And in post, I really love what the ESP is telling me.

[DiGdUb]

thanks for the explanation once again. i get it now.

so the esp system will be more post processing friendly. but i tend not to do much post processing, so i guess leaving it at +0.7 is a better option for me. really appreciate your enlightenment.