Help please! (1 Viewer)

[julie61]

Hi o

I had a go with my brothers 30d and have attached two images that were taken seconds apart, and in exactly the same light, as you can see, one is light and the other really dark, this happens often, does anyone have any idea what could be causing this to happen please?


Many thanks,

Julie oo

 

[rezMole]

Possibly one is metered off the white part of the bird and the other metered off a dark part? Has the camera got spot metering? If it has, and is set so, this can happen with birds that have dark and light parts.

 

[Roy C]

Julie,the first shot is at 1/2500 sec and the second at 1/3200. As they were both shot using spot metering 'rezMole' has got it right, you must have been spotting off a different part of the bird. Unless you can completely cover the metering area with the spot you will get results like this.

 

[Stephen Fletcher]

The difference in shutter speed does not account for the differences in exposure on the 2 pics. 1/2500-1/3200 is only 1/3 of a stop, those 2 pics are about 1 - 1 1/2 stops different i reckon. Were you using auto, where the aperture changed also ?

A prime example of when to use manual exposure i would say.

 

[Roy C]

My mistake, I made a typo - the EXIF actually shows the first shot at 1/1250 sec. BTW Julie was using AV mode for both, its all shown in the EXIF !. Both shots were ISO 250 at f7.1. This is a good case for taking a gander at the EXIF.

 

[Stephen Fletcher]

My mistake, I made a typo - the EXIF actually shows the first shot at 1/1250 sec. BTW Julie was using AV mode for both, its all shown in the EXIF !. Both shots were ISO 250 at f7.1.

So a 1 1/3 exposure difference then.

I have no means of reading Exif on here, and have no wish to. In this case i agree with you about the Exif, but that is not why people wanted Exif posting, look at the replies and you will see that is the case. The Exif still does not tell you anything, it gives shutter speeds, of course, but does it tell you the fist is overexposed, and the second underexposed ? No.

 

[mikfoz]

Bickering aside, this is very likely to be a spot metering issue. There may also be some attempt to compensate in the camera's software depending on what camera it is etc etc which decided in two different directions based on the histogram. Were the images in RAW or JPEG etc etc? All of this may exacerbate the problem. The bright background doesn't exactly help either; in the second shot it may have influenced the exposure.

The obvious thing to do is to use pattern metering in high contrast situations and if the subject is relatively static and you're not sure, use bracketing if your camera works in that way.

Metering's a bugger to get right out in the field in strong lighting. Your subject is brightly lit with shadow, a brighter background, light and dark areas and is a recipe for metering disaster. Sometimes there is genuinely no right solution to get the balance right in a high contrast situation: it's a matter of opinion. Your brain's automatic filtering software is much more adept than a camera at coping. Part of the knack of reading a frame, spot metering the right bit then re-composing is down to the knack of being able to bypass this and see the area of compromise. This is down to years of practice.

I'd actually say that the first pic is acceptably exposed on the bird, darker areas. The second pic is exposing more for the background or even the highlights on the Lapwing and has done a respectable job of getting the highlights on it bang on. You can't have both so a compromise is necessary. Personally I'd have gone for centre weighted metering for this one and metered on the bird then recomposed.

You don't have to read EXIF data to see that.

 

[Roy C]

So a 1 1/3 exposure difference then.

I have no means of reading Exif on here, and have no wish to. In this case i agree with you about the Exif, but that is not why people wanted Exif posting, look at the replies and you will see that is the case. The Exif still does not tell you anything, it gives shutter speeds, of course, but does it tell you the fist is overexposed, and the second underexposed ? No.

LOL o You might not have a wish to read the EXIF and thats fair enough but there is an awful lot of people who find it interesting. Live and let live is what I say :t:

 

[Roy C]

To answer your question Julie, you were using spot metering and this difference is down to the area of the bird that the spot was covering - in the second shot the spot was Predominately over a light area and so it has metered for that and underexposed the whole. When you use spot metering you have to be careful that the area you are spotting from is the one that you want to be exposed correctly.
I never use it myself, much preferring manual but that is just a personal preference. If you do want to use spot then be very careful about the area you spot off of. At the end of the day, the important thing is to get the metering right whichever method you use.

 

[Stephen Fletcher]

Bickering ? I would call it discussion.

The first is not really exposed correctly for the shadows, and the whites are blown, but that situation would have led to an incorrectly exposed image no matter what settings were use, so i wouldnt have even attempted it under those conditions, the only time for contrasty images is very early and very late.. Also as said metering is a very tricky subject, there is no metering system that will get every image right all the time, as a lot of images can have 2 or 3 stops of light difference in them.

I have never said dont use the Exif, all i said was i cant see the point on anyone elses posted images, and here is why. In the old days of film ( and yes, that statement is relevant ) the image was more or less "as taken", nowadays people can do allsorts of magic using photoshop type programmes, and can resurrect an image that may have been underexposed by 2 stops or so. If a processed image such as this is posted,and believe me, some people are good enough with it for you not to tell, what will the accompanying Exif tell you ? It will tell you for example it was shot at 1/4000 @ f8, but you have no idea it was underexposed by 2 stops. So, you have a look at it, and say, ok, ill use those settings next time its sunny, and what happens ? You end up with a shot thats underexposed by 2 stops strangely enough, and spend ages wondering why this is the case. If it were only original images that were posted with Exif, then yes, i can see how that would be useful, ( as in the case in this thread ) but you have no way of knowing what has been done regarding shadow/highlight, exposure, brightness, contrast, noise smoothing, cropping etc etc etc. I know people who use about 30+ layers on every image they take, ( though god knows why, i never use layers unless adding text ) how can you possibly know what they have done ? Thats why i say the Exif is meaningless.

 

[julie61]

Hi Everyone

Thank you all very much for your replies, very interesting reading, I will pass on the information to my brother. I have no idea how he has the camera set up but will keep you informed of the results when he has tried your suggestions :t:

Thanks again all for your time, much appreciated.

Best wishes,

Julie

 

[Roy C]

Bickering ? I would call it discussion.

The first is not really exposed correctly for the shadows, and the whites are blown, but that situation would have led to an incorrectly exposed image no matter what settings were use, so i wouldnt have even attempted it under those conditions, the only time for contrasty images is very early and very late.. Also as said metering is a very tricky subject, there is no metering system that will get every image right all the time, as a lot of images can have 2 or 3 stops of light difference in them.

I have never said dont use the Exif, all i said was i cant see the point on anyone elses posted images, and here is why. In the old days of film ( and yes, that statement is relevant ) the image was more or less "as taken", nowadays people can do allsorts of magic using photoshop type programmes, and can resurrect an image that may have been underexposed by 2 stops or so. If a processed image such as this is posted,and believe me, some people are good enough with it for you not to tell, what will the accompanying Exif tell you ? It will tell you for example it was shot at 1/4000 @ f8, but you have no idea it was underexposed by 2 stops. So, you have a look at it, and say, ok, ill use those settings next time its sunny, and what happens ? You end up with a shot thats underexposed by 2 stops strangely enough, and spend ages wondering why this is the case. If it were only original images that were posted with Exif, then yes, i can see how that would be useful, ( as in the case in this thread ) but you have no way of knowing what has been done regarding shadow/highlight, exposure, brightness, contrast, noise smoothing, cropping etc etc etc. I know people who use about 30+ layers on every image they take, ( though god knows why, i never use layers unless adding text ) how can you possibly know what they have done ? Thats why i say the Exif is meaningless.

Like as already been said Stephen, each to their own. One reason I like looking at EXIF data is to see what Camera was used because it interests me. If you do not want to know then that is fine, no one is forcing you to look but that does not mean that other people should not be interested in some of the EXIF data. I could go on about some of the points in your last post but that is deviating from Julie's original post so I think is best left alone. Have a good day :t:

 

[mikfoz]

but you have no way of knowing what has been done regarding shadow/highlight, exposure, brightness, contrast, noise smoothing, cropping etc etc etc. I know people who use about 30+ layers on every image they take, ( though god knows why, i never use layers unless adding text ) how can you possibly know what they have done ? Thats why i say the Exif is meaningless.

Good point, actually.

I guess it's up to the person requesting critique to state whether the pic is direct from camera or has been tinkered with. In this case the implication is that the pics haven't been mucked about with and the author is trying to get to grips with why two pics taken in quick succession have such different histograms.

In this day and age of being able to "rescue" pics in digital darkrooms we sometimes have to have a 35mm brain still in the field and there's no substitute for experience. That's not to say I never poorly expose a pic, but in the days where you didn't know until developed you used instinct, eyesight and plain old science of light and dark to fend off a disaster.

Personally I try to do as little as possible that you wouldn't have been able to do in a conventional darkroom except for judicious cropping to any of my pics, but that's just me.

A thing a lot of new photographers don't know is that "correct" exposure is a myth. It's all a matter of opinion. Try bracketing a contrasty shot by a good stop and a half over and under and see whether you can decide what's "correct". It'll probably be down to aesthetics. There's a very good reson why if I'm taking time over a landscape pic I'll use a graduated neutral density filter or even a graduated tobacco filter to take contrast issues by the scruff of the neck. Yes, it's obvious if a whole pic is massively over or under exposed, but in the bracketing zone opinion is king. Unless memory is an issue, always play safe and bracket a static subject. Has your camera got a preview function. If so, use it for a test shot so you don't waste memory and tinker with bias or even (horror) use manual exposure and play about. Yes, you can rescue a pic, but it's better to be in the ballpark from the off.

I wonder how many of our forum-goers have ever used a truly manual camera and got results: it seems to be a dwindling skill.

 

[Stephen Fletcher]

I could go on about some of the points in your last post but that is deviating from Julie's original post so I think is best left alone. Have a good day :t:

Please feel free. I dont know why you appear slightly antagonistic to every comment i make Roy ? I get the impression that if i have an opinion on anything whatsoever you seem to lambast that idea, no matter what the content. Opinions are engendered throughout most peoples formative years, heavily influenced by personal experiences, and as such are formulated according to both preferences and logic, and to some degree, taste, however, opinions are exactly that, opinions, and my opinion on a subject is certainly of no less value than your opinion ( or perhaps it is ). I totally understand the reason for your wishing to view Exif data, but have i ever said it was wrong ? I have learnt over many years you cannot please everyone all the time, but disagreeing with an opinion does not mean either viewpoint is wrong, but i would go as far as to say i would never lambast anyone for having an idea that was reciprocal to mine. I merely tried to explain the equally as valid argument for not displaying it. I never intend being antagonistic, if i comes across that way then perhaps its my lack of correct English language usage, but i have never claimed it was perfect.

I am sure Julie will have no objections as her question has been answered satisfactorily.

Good point, actually.

I guess it's up to the person requesting critique to state whether the pic is direct from camera or has been tinkered with. In this case the implication is that the pics haven't been mucked about with and the author is trying to get to grips with why two pics taken in quick succession have such different histograms.

I appreciate the very valid point you made there, which is an excellent case for Exif being displayed, and can obviously see the relevance of the data being required. It led to a quick diagnosis of the problem, without which the cause would have not been apparent. However, i stand by my reasoning for purely interest and potential usage purposes.

There's a very good reson why if I'm taking time over a landscape pic I'll use a graduated neutral density filter or even a graduated tobacco filter to take contrast issues by the scruff of the neck.

I have never been able to get to grips with landscapes, filters etc, but greatly admire those that do. I understand the theory, thats no problem, but i dont seem to have the eye for the composition, no idea why.

 

[seaspirit]

Well,

I can offer another explanation. Less likely but nevertheless possible.

The Bigma I own had initially a problem with opening and closing of the aperture.
Means after setting f on the camera the correct exposure was determined under the assumption that the lens was wide open. That should be the case and usually is. My lens had the problem that randomly once in a while the aperture got stuck after taking a shoot, leading subsequently to overexposed frames.

Easy to miss the problem when shooting with max. frame rate, espcl. if on a f 6.3 lens the aperture is stuck at 8. Most times the aperture got unstuck within seconds and worked for a while till it happened again.

However, didn't take long to pinpoint the problem and eventually the lens went back for service (during the winter at -30 the problem worsened). Took then only 6 weeks to get it back from service (seems the normal turn-over time in this part of the world, for most manufacturers) and now it works smoothly. As expected all work was done under warranty (10 years for EX lenses here in Canada) but one could wish for a bit faster turn around ........

Ulli

P.S. In this situation the EXIF will not show the problem as the camera assumes the lens wide open and calculates exposure times accordingly