Focusing versus exposure

[Rafa]

Hi experts, how are you? I hope taking so many pictures!

I would like to ask you about some technical adivice. I'm new on DSLR world but I'm studying it and trying as much as I can, the only mode I use is manual mode.

So, going direct to the point, the subject is exposure. Sometimes I notice that I should measure the exposure of my photo in one object which is not the subject of my picture. Lets say that I'm taking a portrait of a person which is in the left side of my pic but I would like to measure the exposure in another object which is on the right side of the picture, is it even possible or I'm talking bull****?

Sometimes when I am taking a picure the exposure looks over/under exposed, I'm trying to change the exposure mode and playing with matricial metering, spot metering and the other two my camera (Canon 6D) offers. I am getting good results after taking some pictures but I feel like there is the jump of the cat that I didn't get yet.

What advise would you give me regarding it?


Best regards,

Rafael (amateur photographer)

 

[Rafa]

Another example, I focus on one object then I recompose the picture. The exposure was measured on the object I focused, right (considering spot metering)?

 

[Derrel]

You might want to learn more about how to do "AE Lock" , using Aperture Priority automatic metering mode, or as Canon calls it Av mode".

Here is an article written by Canon itself. Canon DLC: Blog Post: AE Lock done right: AE Lock with Hold

Another issue: in MANUAL exposure mode, Matrix-type or multi-segment evaluative metering doesn't make as much sense as using a center-weighted metering approach. Matrix-type metering measures the whole, total frame...I think that's not the best way to use a Manual exposure mode for deliberate picture-taking. I think in Av or Tv or P mode, that Matrix-type metering makes more sense.

Overly bright backgrounds or foregrounds can cause the meter to give unreliable readings. Keep working at it. You CAN measure the exposure at various places in the frame, using either Spot Metering or Center-weighted metering. Those two modes are probably the best for Manual exposure setting mode.

 

[CAP]

I know only in top DLSR's you can use Selected AF Point Spot Metering.There it meters on the currently selected AF point or even meters on multiple selected AF points.

As i am able to do this on my Canon 1DX.

But if you are shooting a subject that has back drop behind like in a studio, then you would need to use center weight average this recommended by the manual.

http://www.photoplusmag.com/files/2014/04/infographic.jpg

 

[KmH]

All of Nikon DSLR's use the selected focus point as the area being metered when Spot metering mode is selected.

From the Nikon D50 specifications:

Spot - Meters 3.5-mm circle (about 2.5% of frame) centered on active focus area

The Nikon D50 was Nikon's first consumer grade DSLR and was sold from June 2005 until November 2006.

Nikon's 1st Prosumer grade DSLR - the D100 - was introduced on February 21, 2002 and produced until the end of the 3rd quarter of 2005.
From the Nikon D100 specifications:

Spot - Meters 3-mm circle in center of frame; with CPU lens, metered area linked to selected focus area

Nikon's 1st DSLR - the D1, introduced on June 15, 1999 - was a pro grade SLR but also Spot metered at the selected AF point.

Spot: Exposure determined by 4 mm circle in center of frame (approx.2% of frame); when a CPU Nikkor lens is attached, any of the
five focus areas can be used for spot metering.

https://support.nikonusa.com/app/answers/detail/a_id/13948

 

[BlackSheep]

In addition to the advice you've already been given, just a note - if you aren't already, shoot in raw mode not jpeg. That way, while you are learning how to do proper exposures with your new camera, you still will have the ability to adjust your exposures to compensate for minor errors during post-processing afterwards.

 

[Rafa]

Guys,
One thing that I love about this forum is that in less than five minutes I've got a precise answer regarding my doubt. What I notice is that as much precise and direct I'm my doubt the better is the quality of the answers I get. So I'll try to keep my questions like that.

CAP,
Actually what I'm looking for is measure the exposure in a different moment of my focus. I mean first measure the exposure and after that focus on my subject and recompose, after that take my picture. I went this weekend in a Buddhist temple here in Brazil, it was about noon and I the wheater was very clear and sun was shinning. This was my weather conditions at that moment. It happens that the sun light was making me struggling with focus and exposure to take good pictures. Sometimes I need to take three or for to get a good one. I know it is usual but I felt like I was struggling with the exposure.

Derrel,
You helped me to choose my Canon 6D which I'm in love with. And again, you put the cat out of the sack. The AE Lock was exactly what I was looking for, a way to control the exposure separated of my subject. Now I need to practice and also the AE Lock with Hold which looks even better. I usually research on YouTube after reading the article to view how it works on my camera, which gives me a better understanding of this feature. Again, thank you for the free class.

 

[Rafa]

In addition to the advice you've already been given, just a note - if you aren't already, shoot in raw mode not jpeg. That way, while you are learning how to do proper exposures with your new camera, you still will have the ability to adjust your exposures to compensate for minor errors during post-processing afterwards.

BlackSheep,
This is a good advice but I don't know how to adjust pictures in softweres like Photoshop, Lightroom, Corel Draw and any other. So as I'm a curious guy I'll keep with .jpeg now and take in considertion your advice and learn how to use any of theses softwares. By the way, I know it is a personal choice which one you suggest?

 

[Derrel]

Keep at it! You will become better at running the controls and at making photos with the new 6D!

 

[Rafa]

Guys,

This YouTube video gives a clear idea of how the AE Lock and AE Lock with Hold works and how to activate tihs feture.

Canon EOS 5D Mark III - Tutorial AE Lock with Hold Feature



Best regards

 

[dennybeall]

Rafa,
Software choice is not only about personal choice. Different packages have different capabilities and also very different cost. The more capability the more cost. If you don't need full pixel level manipulation and lots and lots of other features then you don't need to spend the money for the full Photoshop CC package and a bunch of add-ons.

 

[TCampbell]

Rafa,

You really want to expose the for the "whole" image... not just the subject. If there's something in the background which is over-exposed it may become a distraction ... drawing attention away from the intended subject. Deliberate "high key" and "low key" photography are exceptions to this -- so it's more of a guideline than a rule.

Ideally, you take multiple readings to make sure everything is within the dynamic range of the camera (typically within a few stops of your intended subject exposure.) If it isn't, you would typically do something about it... move the subject to different location with better lighting... use flash to control the subject exposure and bring it closer to background exposure, etc.

I use an "incident" light meter (a hand-held meter... not build into the camera) which allows me to meter multiple locations of interest and it has the ability to take multiple readings with the understanding that they're actually all intended for the same single exposure. It really looks for a "high water mark" and "low water mark" exposure value then calculates the "middle" exposure which will do the best job of capturing everything without having any blown out highlights or clipped shadows.

Keep in mind that everything visible in the camera frame counts when judging the quality of the image... whether or not it's your "intended" subject.

As for the RAW advice... "JPEG" is a good format for "final output" (you are finished making adjustments and want to share the image or print the image... JPEG is great for that.) If the image needs adjustment, RAW is better.

JPEG was invented as a way to represent an image that looked pleasing to the human eye but did not take a lot of storage space nor a lot of bandwidth to transmit on the Internet. The compression algorithm takes advantages of weaknesses in the way that the human eye works. We are a little better at noticing subtle differences in brightness and not so good at noticing subtle differences in hue.

Suppose you take a photograph of a bride wearing a "white" wedding dress. The JPEG algorithm would take all the pixels which are "nearly" (but not technically "exactly") the same... and just flatten them so that they ARE the same. The rules for 'RAW' state that no changes can be made which result in a loss of original data. So the JPEG file has lots of pixels which are NOW all identically even though originally they were all technically just slightly different... because our human eyes probably would not have been able to detect the difference. But the RAW image will keep everything whether we notice the difference or not. ALSO... RAW is 14-bit image data on your Canon camera model (it can technically vary by camera but 14-bit is pretty common). JPEG is 8-bit data format on EVERY camera.

But now suppose the image was slightly over-exposed, so you decide to make some exposure adjustments on the computer (even Canon Digital Photo Professional which was included on the media that came with your camera can do this). If you shot in RAW, the original data is all there... so as you alter the exposure, all that detail is recovered and you can notice the subtle lace patterns of the white wedding dress. Meanwhile, if you shot JPEG, the JPEG algorithm has compressed all the data which was "nearly" the same to make it "exactly" the same because our eyes "probably would not have noticed the difference". But now when you try to correct the exposure to recover the data in the highlights you end up getting a muddy flat dull gray blob that has no detail in it.... this would be because the JPEG algorithm trashed the original data because it didn't think we'd be able to tell the difference.

For this reason, shooting in RAW is generally preferred because it preserves that data. Go ahead and shoot JPEG if you are more comfortable... but keep the thought in the back of your mind that you should probably learn how to shoot RAW and adjust the images as this will be a milestone in your ability to improve your results.

 

[Rafa]

TCampbell,
Thank you for the detailed explanation of exposure and RAW files. I'll get some software and play with it, search tutorials to learn at least the basics to adjust my pictures.

Guys,
As a beginner in DSLR world, do you recomend any metering mode? I usually use the partial and spot metering of my camera. And depending on the results I see in the LCD I try the others too.