Please Help Me Understand DoF Preview / Setting Effect

[Pedr]

I've just made the switch from a 5D3 to an A7R2. I'm using a Metabones MkIV adapter so that I can use my Canon glass.

 

I'm really struggling to understand how to achieve a true preview of the exposed image.

 

On my 5D3 I could hold down the DoF button and view the rear screen. The camera would stop down the lens, but boost the brightness so I could clearly see what would be in focus and what wouldn't. By zooming into the image, this gave me fine-grained control over focus - I could pick the furthest object I needed to be in focus and ease the focus until it was just in acceptable focus, thus maximising my depth of field. 

 

On my A7R2 with Setting Effect set to On I can assign a button to trigger Shot Preview. This appears to be equivalent to DoF preview. The camera stops down the lens and boosts the brightness of the image to compensate. I can then see what is in and out of focus. However I cannot magnify the image with this button depressed and pressing the button when already magnified has no effect.

 

So how can I get a preview that shows me accurate DoF and allows me to magnify the image to focus?

[adwb]

on mine I never use it but set mine up like your and the only way seems to be manual focus seems to work and allow magnification but that's not what you want.

[caegear]

I am not too familiar with Canon cameras (other than short borrows), and I have not heard of this DoF button. I am curious to know what it does. Is this something other than a digital translation of settings displayed on the back LCD? I thought one advantage of the Mirrorless system was that this was not needed since both Viewfinder and LCD are allready such a translation of settings (ie: whatever settings you choose are shown both in evf and on LCD if "Live View Display" ("MENU" -> "sprocket wheel" / "gear icon" -> "3" -> "Live View Display") is set to "Setting Effects ON")?

 

I also dont have a "Shot Preview", but one "Shot Result Preview" and one "Aperture Preview". However, I do feel I am able to do what you describe simply by using Focus Magnification in MF / DMF on A7II. I zoom in and set focus and DoF as I want (Could use "Focus hold" on one button too if AF/DMF maybe?)

I am not sure I understand what sircumstances would call for the need to use exposure settings that need "Shot Result Preview" other than if you are using strobes, flashes or other triggered light sources (without compose light)? Is that the case? Are you in a studio (or wherever) and using some triggered light source? I had an a6000 once, and I do seem to remember I could pop the mini-flash and that would automatically make half-pressing shutter btn show a "Shot Preview". It was essential because camera settings was based on a light source that was not there until i pressed shutter and triggered it. I dont have a flash for my A7II and cant test if attaching one would let me have this "Shot Preview" (That might very well be the "Shot Result Preview" I see in my A7II settings) set in on half-press or on any other programmable button.

 

Sorry if I have misunderstood your question (and for not doing a spell-checking). Maybe someone more familiar with triggered light sources and /or Canon gear can help?

 

C

 

Edit: I see this (at least related) is discussed here: http://www.sonyalphaforum.com/topic/6243-real-time-image-adjustment-display-onoff/. I only have MF lenses and I guess thats why I have never thought of this DoF-thing. Does the Metabones adapter adjust aperture for your lenses when you change Aperture on the body or Is that the thing? - that it doesnt before pressing shutter and you would like it to? Maybe this is a Metabones-related problem-thing?

[JCC]

Have you tried turning on focus peaking?

 

JCC

[Username]

DoF changes as you change f-stops. However, on some cameras, 

viewing brightness and fucusing ease also change as you change 

f/stops. To maximize viewing and focus ease on affected cameras, 

the f/stop does NOT physically change when you adjust the f/stop 

control. Instead it stays at the most eyeball-friendly position to aid 

you viewing and focusing. Only during the brief moment of actual 

exposure does the lens's iris move to the actual physical position 

that creates the f/stop you set on the f/stop control. 

   

So, in normal viewing and focusing with such cameras, even tho 

you've set maybe f/11, you are viewing and focusing at f/2.8 or 

whatever the wide-open f/stop is for your lens. So even tho the 

image you record will have the DoF provided by f/11, the viewing 

image showed you only the DoF provided by f/2.8. 

   

A DoF preview control overrides the protocol described above and 

lets you preview the effect of increased DoF at the smaller f/stop. 

Sometimes the image is so dark it's difficult to use the preview, but 

you get used to that. Also, it's not ALWAYS terribly dark, just dim. 

  

DoF preview is never [to this date] a digital simulation. It's analog, 

a real optical event. However, if you have a live view camera, the 

camera may apply extra gain to brighten the view that would have 

otherwise appeared quite dimmed when using the DoF preview. 

The DoF effect is real, is analog, even tho the brightness has been 

digitally compensated for your convenience. 

[michelb]

On traditional SLR's, the lens is staying at full aperture until you release the shutter so the depth of field shown in the finder is always at its minimum which is not really the case if you or the camera choose an aperture that is smaller  

 

To help preview on SLR's, the most advanced models have a depth of field preview button that once pushed, stops down the lens at the selected aperture thus providing a much closer rendition of what will be in or out of focus. Trying to focus after the fact is not something i have tried before on SLT or mirrorless.

 

ON mirrorless cameras with native lenses, the lens is normally at the working aperture so this feature is not really necessary. When using adapted lenses like Sony/Minolta using the LA-EA type adapters, the lens behaves as if it were on a true SLR thus staying wide open to allow the focusing mechanism that is built into the adapters ( traditional PDAF sensors ) to do its work. Sony added the DOF button possibility for use with these but i have never tried it to see if it allows fine tuning of focusing through the magnifier.

With other adapters like your Metabones, the ability to use this will depend on the behaviour that the adapter allows. If it is already focusing at the working aperture like native lenses, then you don't really need to use it.

 

Using manual focus should allow the magnifier to come into play then stop down to identify far/near focus zones if your Metabones actually opens the lens for focusing. If it is already at working aperture,you don't really need this stop-down to come into play.

[Navman50]

I use a metabones IV adapter with a Canon EF mount TS-E 24 mm II and I have gone into my custom

button settings and set the AEL button, which I never use for that purpose, to 'Shot Result Preview'. When

focusing the lens is wide open, but using this button shuts the aperture down for preview purposes - works

a treat.

[Username]

On traditional SLR's, the lens is staying at full aperture until you release the shutter

so the depth of field shown in the finder is always at its minimum which is not really

the case if you or the camera choose an aperture that is smaller  

 

To help preview on SLR's, the most advanced models have a depth of field preview

button that once pushed, stops down the lens at the selected aperture thus providing

a much closer rendition of what will be in or out of focus. Trying to focus after the fact

is not something i have tried before on SLT or mirrorless.

 

ON mirrorless cameras with native lenses, the lens is normally at the working

aperture so this feature is not really necessary................

    

"ON mirrorless cameras with native lenses, the lens is normally at the working 

aperture so this feature is not really necessary................"    This not true of all 

live view ["mirrorless"] cameras. True of some. The weirdest aspect is that on some 

models it's both true and not true, depending upon which exposure mode is in use !    

    

################################################################

   

The OP specifies an a7R-II. My own version is the basic a7-II, and it definitely uses a  

physical/mechanical DoF preview. There is an image preview that goes way beyond 

the "live view effect preview" which mainly governs whether or not viewing brightness 

will digitally mimic the final exposure. The full image preview feature [sorry, I forget the 

Sony Jargon term for it] is engaged only momentarily at the push of a button [user can 

assign button of choice/preference] and it previews color shift, exposure, real DoF etc.   

  

This full preview includes mechanical DoF preview. When you push the button you do 

see DoF increase [if using a smallish aperture]. When the lesser preview function, the 

"live view effect preview" is the only preview in use, the image brightens and darkens 

as you dial the f/stop control up or down, but you can see that the DoF shown in the 

finder or monitor never changes. "Live view effect preview" is either enabled or not on 

a continuous basis, via a menu choice. The full image preview [whatever it's called] is 

never available continuously ... it's always momentary via pushing button. 

[Username]

Have you tried turning on focus peaking?

 

JCC

     

This is a really cool DoF indicator ... not a preview in 

the visual sense, but visually it's a graphic indicator, 

a very graphic indicator. 

   

However, to use peaking as a graphic indicator you 

must also have a lens operating at working aperture.     

That is, the iris is physically closed down to the f/stop

indicated on the f/stop controller. 

   

With the iris operating at working aperture [iOW, DoF

preview is constant] you can actually see the peaking

color spread or contract in depth, as the actual DoF 

goes deeper or shallower as you dial in large or small

f/stops. It's a very graphic "teaching aid", and a useful 

working tool once you get used to it. 

[jaymayugaphotography]

you can assign the "APERTURE PREVIEW" to any button in custom settings