Focus in live view

[ronniex]

I am a beginner, how do i focus on a object in the foreground and keep the background in blur then switch keeping the background in focus and foreground in blur. I can do this quite easily in live view by shifting the focus box to each subject.But when i try to do it viewing through the view finder the only way i can do it is by focusing on the subject and shifting the framing. i am using Av mode with my canon 1100d and a 70-210 lens.
Peter

[RobertsMx]

I am a beginner, how do i focus on a object in the foreground and keep the background in blur then switch keeping the background in focus and foreground in blur. I can do this quite easily in live view by shifting the focus box to each subject.But when i try to do it viewing through the view finder the only way i can do it is by focusing on the subject and shifting the framing. i am using Av mode with my canon 1100d and a 70-210 lens.
Peter

Use Local Focus (a term used in my Sony cameras, Canon should have similar feature), or Manual Focus. My Sony A55 uses Phase Detect AF regardless of using the view finder or the LCD, so the same technique applies. If at least one of the points of interests falls outside the focus points, manual focus is a good option.

In case of Canon DSLRs, view finder uses Phase Detect AF whereas LCD (Live View) uses Contrast Detect (CDAF). And CDAF allows you to move the focus box around. When using PDAF (using the view finder), you will have to select local spot focus, and if any of the points does fall outside the AF points available, use MF.

[Manfred M]

Peter, you are looking at Depth of Field (DoF) and the hyperfocal distance. Check the tutorial on this site: https://www.cambridgeincolour.com/tu...h-of-field.htm

Your viewfinder is showing what you see when the lens at its maximum aperture, while live view stops down the lens and you get a more visual representation of the final image. Frankly this is something one tends to learn when one shoots a lot. A small aperture number (f/2.8) for instance, will give you a fairly shallow DoF, whereas a larger aperture (f/16 or f/22) will result in everything being in focus. A wide angle focal length will tend to produce images with a large DoF while long focal lengths tend to produce images with shallow DoF.

In photography, one usually tries to ensure that the subject is sharp, and the background is thrown out of focus. Out of focus foreground is not always good from a composition standpoint. I rarely shoot live view and have learned what works completely through experience.

[dje]

Hello Peter

As Manu indicates, there are two distinct types of autofocus for Live View and Viewfinder operation.

With Live View, the main camera sensor is used for autofocus and this can be done in virtually any part of the screen. With Viewfinder mode, auxiliary small sensors are used for autofocus and these have light directed to them via a secondary mirror. The number and location of these sensors determines the number of autofocus points. In the lower end cameras such as the 11000D or my 600D, there are only a small number of these (9) whereas the higher end cameras have considerably more.

You can leave it to the camera to decide which focus point to use or you can set it manually. I prefer to set it manually and use the centre point all the time and just re-frame after setting focus. The other points are not cross type and are not as effective. In any case, it's unlikely that you will always find one exactly where you want it.

Have a close look in your manual. It should explain this in some detail.


Dave

[jcuknz]

Cameras these days have alternative focus and exposure lock buttons to handle these situations and your manual will explain how it works .... or as I think you are doing holding half trigger and re-framing .... the multi-spot focusing systems are good when in a hurry but for more measured situations I prefer the single centre point [ or elsewhere with my touchscreen occasionally ] and reframe technique.
I have never manually focused with good result since I changed to digital [live view] and it usually proved to be unsatisfactory after AF had earlier failed me ... tricky stuff like the moon in thin cloud. But with my current Panasonic MFT camera I have the option of a very small target area which I think is the solution to AF working properly as I want it to do for me.