I have set my camera back button AF-AE Lock button for AF-On and now i focus my pictures by holding that button and not the shutter button and I have assigned my Fn button for AE-Hold as i want my exposure to lock but I am getting confused here that do I have to set my focus and exposure lock at only one point only or I can set my focus on one point and lock my exposure at some other point ? I have attached picture with this post where i lock my focus and exposure on the eyes and you can notice that highlights are blown out on the face so should I have focus on his eyes and lock exposure on his face to get rid of this highlights blown out problem on his face ? Plz Help
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How to make good use of AE Lock Hold ?
- Thread starter ahsan26
- Start date
This is exactly how I do it. As soon as you focus on something let the button go. Your done with focus at this point. Then recompose to set exposure. Of course it depends on what exposure mode your set on. If set on spot the result you got makes sense. Try using center weighted and see how that performs.
I have set my camera back button AF-AE Lock button for AF-On and now i focus my pictures by holding that button and not the shutter button and I have assigned my Fn button for AE-Hold as i want my exposure to lock but I am getting confused here that do I have to set my focus and exposure lock at only one point only or I can set my focus on one point and lock my exposure at some other point ? I have attached picture with this post where i lock my focus and exposure on the eyes and you can notice that highlights are blown out on the face so should I have focus on his eyes and lock exposure on his face to get rid of this highlights blown out problem on his face ? Plz Help
Depends on the focus mode settings on your camera if you are in af-s or af-c. If you are in af-c the focus will keep changing while you hold the back button, in af-s once pressed it locks and stays the same whatever you do unless you release and re press.
The problem you seem to have is you were probably using centre spot exposure and the slightest change in where the spot is pointing at will change the setting. As @FastGlass says try centre weighted or even matrix.
Thanks for the answer. I 95% of the time use AF-S Focus so i believe as mentioned if i focus using the back button and then let it go my focus will remain intact and then i can meter my scene wherever i want but then why i need to lock my exposure ? Shouldn't i just meter the scene accordingly and press the shutter ? Let it say I am using Spot Meter. Or what difference it will be if i am using other metrring modes as matrix or centre metering ?
Thanks for the answer. I 95% of the time use AF-S Focus so i believe as mentioned if i focus using the back button and then let it go my focus will remain intact and then i can meter my scene wherever i want but then why i need to lock my exposure ? Shouldn't i just meter the scene accordingly and press the shutter ? Let it say I am using Spot Meter. Or what difference it will be if i am using other metrring modes as matrix or centre metering ?
You don't need to lock your exposure if you are using matrix metering as it takes in the whole scene and works out an average exposure. Spot metering is amazingly sensitive if you move the spot just slightly it will change the exposure. For example to avoid the blow outs on the highlights then put the spot on them and then lock the exposure, then frame the photo as you want and shoot. This will cause some of the darker areas to be more dark but thats the trade off. You can always recover the dark areas in post. As you have a D750 you can use the new exposure option of highlight weighted metering, this will solve your problem in one go and you won't need to lock the exposure.
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You don't need to lock your exposure if you are using matrix metering as it takes in the whole scene and works out an average exposure. Spot metering is amazingly sensitive if you move the spot just slightly it will change the exposure. For example to avoid the blow outs on the highlights then put the spot on them and then lock the exposure, then frame the photo as you want and shoot. This will cause some of the darker areas to be more dark but thats the trade off. You can always recover the dark areas in post. As you have a D750 you can use the new exposure option of highlight weighted metering, this will solve your problem in one go and you won't need to lock the exposure.
The D750 is better than most of the cheaper digicams for exposure options and it has superb focus with my f1.4 50mm prime lens. However, all digicam exposures suffer the same problem. Current sensors have limited dynamic range to handle the highlights and lowlights (compared to film). Whilst you can fiddle with lowlights in post, overexposed highlights once blown cannot be recovered. The first thing I did with my D750 was to practice shooting different scenes on a bright sunny day then go and have a look at the RGB clipping in preview. It is a pitty there is no live 'zebra' before taking the shot. But afterwards, you can see how well the different metering modes work with highlights.
I never rely 100% on the camera metering to get exposure right. After doing some test shots I found that dialling in an extra stop protected most scenes from highlight clipping. If you really want to be sure, try checking the histograms and clipping previews, then choose the metering modes that work best for you. I have always been surprised that even 4 stops under exposed can be pulled back in post. But over exposure is usually a lost frame.
Don Kuykendall_RIP
RIP :(
Good advice.
Small point, the D750 is a DSLR not a digicam
I think he is just using the term to mean a Digital Camera vs a Film camera.
I didn't mean to offend anybody with my semantic description. But all electronic cameras use an electronic sensor to capture the image and then electronically process the data to store on digital memory. Whilst 'Digicam' may not be the semantic description some want to hear, that is the same principle used in the D750 which is a 'hybrid' of a conventional film SLR and a Digicam. Since the D750 shoots HD video, it is closer to a Digicam than a SLR because it uses 'Live View' mode, the same as smaller consumer digicams and mobile phones.
What Meter you people use mostly ? beauase i mostly stay away from Matrix Metering as its really difficult to get a proper exposure...I used to have centre metering mostly but now I am mostly using spot..Also please mention does the spot metering works only with the centre focus point or it move along with the change in focus point ?
What Meter you people use mostly ? beauase i mostly stay away from Matrix Metering as its really difficult to get a proper exposure...I used to have centre metering mostly but now I am mostly using spot..Also please mention does the spot metering works only with the centre focus point or it move along with the change in focus point ?
I use them all depending on the scene, but find I am using highlight compensation probably the most often. The spot metering changes and follows the focus point.
Blade Canyon
Senior Member
For back button focusing, there is no reason not to use AF-C, even with a single focus point. That way, if your subject is not moving, you can focus, release, recompose, and shoot. But if your subject is moving, you can hold the back button down and keep the auto-focus working while you shoot. That's one of the advantages of BBF.
Even with the blown out highlights you complain about, that is a wonderful picture of that boy. If he is your son, you will love it much more in many years.
Even with the blown out highlights you complain about, that is a wonderful picture of that boy. If he is your son, you will love it much more in many years.