Auto-exposure on the F3 - even with manual lenses

[Dennis Hingsberg]

I originally wrote part of this reply in response to some criticism the Sony 18-270mm zoom lens was receiving. In particular the "ramping" - which is experienced when zooming throughout the range of a zoom lens which does not feature a constant aperture throughout.

The Sony F3 offers an amazing feature buried in the menu that was meant for automatically controlling exposure levels and can be used to address lens ramping, amongst a series of other shooting conditions....

Within the CAMERA SET menu of the F3 is the TLCS feature (total level control system) which can be used to automatically adjust your exposure making your setup very flexible for ENG or run & gun shooting not to mention real handy for other types of live (or non-live) shooting where scene brightness might change continously (ie. in and out of car or house, or panning from hockey rink to crowd, etc..)

Basically the feature allows you to setup the F3 with a preset amount of gain (to boost) and shutter speed (to cut) to automatically adjust exposure within these parameters BUT WAIT THERE IS MORE - you can define the amount of time in seconds it takes to auto-adjust so that changes are GRADUAL and not done abruptly. I've personally been using this for time-lapse shots where exposure may change slightly over time and I've also used it for scene pans where contrast or brightness levels change throughout the scene. This is GREAT if you don't want to manually ride the IRIS on the lens, and especially if you are using non-de-clicked manual lenses like I am.

For any "lens ramping issue" the TLCS feature would easily take care of most problems.

To configure it:

- Go to CAMERA SET -> TLCS Menu.
- Turn AGC to ON.
- Set your AGC Limit to the max. amount of gain you want the camera to introduce when necessary. ie. +3db.
- Set your A.SHT LIMIT (shutter limit) to the max. amount of light you want to cut remembering that 1/100 is double the amount of 1/48, and 1/200 is four times that of 1/48, etc.. etc..
- Lastly, set your SPEED to the amount IN SECONDS that you want the wonderful F3 to respond to light changes so they do not appear abrupt. (may required some testing and finessing)
- You can ignore the other settings in the menu, these ones are the main ones and DONT FORGET to turn it off when you don't want to use it, man it will mess you up when you start adjusting your LENS IRIS and nothing happens! lol




One issue if you use A.SHT.LIMIT is that your shutter speed will change from your default, say 1/48 so you need to consider that based on what you are shooting.

[Leonard Levy]

Thanks, I've never figured out what TLCS is and there are rare circumstances where I might use it especially as the F3 is so clean in gain.

[Dennis Hingsberg]

Leonard I'm glad you found this useful.

The F3 has changed the way I have thought about using GAIN in-camera in general because it is so clean. Not in a MILLION years would I ever want to introduce gain into my shots - even if I needed it because I was afraid of the noise. On the F3 however you can definitely get away with it.

In a pinch I have even used the built-in ND filters (3 and 6 stops) which in some cases were too strong but I just combined it with a gain of +3db or +6db to bring myself back up one or two stops... this is lazy I know, but very handy if you are trying to maintain a certain DOF and don't have time to stack ND filters...

[Alister Chapman]

You can have a constant shutter speed simply by turning on the manual shutter switch and setting your desired shutter speed. This overrides the TLCS auto shutter, so you can still have AGC, but now with a fixed shutter.

TLCS is very useful for time-lapse sunrise and sunset shots. You can even flip in or out ND's as needed with only minimal disturbance to the time-lapse sequence as the cameras auto gain will set the exposure very precisely. The only problem is that it's easily fooled by any bright light sources within the shot.

[Thomas Kaufman]

Hi everyone

A quick question about TLCS: how does one turn it off?

Also, Alistair's post it says "Set your A.SHT LIMIT (shutter limit)" but this is grayed out on my F3 v1.4

thanks

Tom

[Dennis Hingsberg]

Thomas, it was my post not Alister's!

Even though you will see TLCS in your viewfinder, it is off until you turn it on. ie. turn on the shutter or gain settings within the TLCS menu. To ensure it is off go in the menu and make sure AGC is OFF, and AUTO SHUTTER is OFF.

Under the VF menu where you see TLCS that is only to hide it from your viewfinder, not actually enable/disable the TLCS function itself.

If yours is greyed out check your shutter switch at the front of your F3 to see if shutter is on or off.

[Dennis Hingsberg]

Also if working with a "fixed shutter" as suggested by Alister the F3 will never be able to cut light exposure to more than what the camera will do set to -3db gain. To cut exposure beyond that you would need to add ND filters or let your shutter do some of the work.

For time lapse video "shutter speed" really shouldn't impact you unless you really want to preserve blur on faster moving subjects. For very slow moving subjects like sunrise, sunsets, or turtles, a faster shutter should be fine.

[Thomas Kaufman]

Dennis,

Thanks for the post, it's very helpful.

I'm looking to see if there's a way to assign the TLCS function to a button, but so far no luck. In fact, since I'm using an Alphatron EVF, most of the functions I could assign to a button are not visible thru the viewfinder. I'm feeding the EVF from the SDI out connection. Is there a better way to go?

thanks

Tom

[Dennis Hingsberg]

Sorry can't help on that last one.

[Alister Chapman]

You can't assign it to a single button because there is no single on/off function. It's probably better to think of it as a set of limiters for the various auto functions. I too connect my Alphatron to the SDI out (not the A or B out).

[Thomas Kaufman]

Originally Posted by Alister Chapman

TLCS is very useful for time-lapse sunrise and sunset shots. You can even flip in or out ND's as needed with only minimal disturbance to the time-lapse sequence as the cameras auto gain will set the exposure very precisely. The only problem is that it's easily fooled by any bright light sources within the shot.

Alister,

What if you changed the mode of the TLCS? Would either 'backlight' or 'spotlight' modes help in time lapse of a sunset?

Cheers,

Tom

[Alister Chapman]

It doesn't really help as all they do is either increase or decrease the overall exposure level. It's till not intelligent enough to deal with a blazing red sun against a bright sky. Having said that if you use the exposure offset to stop down by a stop it normally does a reasonable job. Better in most cases than I could do myself trying to ride the exposure.

[Dennis Hingsberg]

Here is my first time lapse sunset attempt manually pulling iris on the F3. Pulling iris is a very bad idea, as it results in a lot of varying exposure and stepping of the sun as its shrinking whereas I would have liked the shrinking to be more smooth and constant.

This was before I learned of the TLCS feature built into the F3. I've since done a few sunrises but haven't posted any of it online. It's tricky starting in the dark waiting for a sunset and not knowing your END exposure settings so I suggest shooting a sunset first so you get familiar with what your settings might be around approximately.

Coincidentally, the night I shot this was the night my wife gave birth to Evan, our baby boy!
Enjoy!

Sunset over Lake Simcoe - YouTube

[Thomas Kaufman]

Hi Dennis

First, congrats on the birth of your child! Also, this is a nice sunset shot, but Is ee what you mean about trying to ride the aperture. I've also done that with about the same results, which is why the TLCS setting seems like a good idea, at least to try out.

Has anyone done this,a dn are the results posted someplace?

thanks

[Dennis Hingsberg]

Yes thank you! Evan is now a year old but thankfully he was born AFTER I shot the sunset not during it.

In the above video, the original is quite bad. In the video shown here what I had to do was cut parts of the clip and overlay them by 2-4 frames and do a very subtle fade by using opacity function. So the net effect are very fast frame dissolves.

TLCS is a much better way to go and if you enable shutter and gain controls the camera will pretty will be able to handle exposure up to 3 stops over middle exposure and 2-3 stops under. That is still not really enough to go from starting in the black night to the sun fully exposed in the sky...

Also another tip is to bring a compass and figure out exactly where the sun is going to rise or go down. It is not going to be EXACT due EAST or WEST so you have to try it or find some online calculator that will tell you how many degrees it will be for your given location.