Still needing a more concrete explanation on blackshading. Several questions.

[Roger Alexander]

I've read the forums, watched tutorials etc. but I still dont have a 100% firm understanding on some black shading issues and questions I have regarding the process. Some of the video tutorials out there are for DSMC1 bodies and don't detail the new processes for DSMC2 and autoblackshading. So I'm confused. I will list my concerns below. Sorry if my questions are annoying, I just have never grasped a firm understanding of what's happening in the process and what to do in certain situations; and I think it's affecting some of my images. I want to make sure I have a thorough understanding in laymans terms, so please don't reply with "read the handbook", I've looked at it and still have questions. If you know the answer to a question please put the # before your reply! Thanks so much!

1. From what I understand, you should black shade when you are shooting in extreme hot or cold conditions and when the temperature changes about 30 degrees F from the previous temperature. But the Raven does auto-blackshade when you turn the camera on right? So shouldn't it automatically create a new profile based on the temperature and settings that the camera is turned on at?

2. What exactly is the camera doing in the auto-blackshade process. Conceptually I know it's removing pattern noise from the image, but like, in terms of file creation and settings. I'm not sure if I'm wording this right. Does one profile cover a variety of situations?

3. Do you have to create a new black shade profile for each temperature you might operate at indefinitely? If so, how do you get the camera to the desired temperature to calibrate to? Or does the camera raise the temperatures itself?

4. If you have to make a new profile for different temperatures, when you are in the field and your camera reaches one of those "next level" temperatures, do you have to manually go into the settings and choose the profile you created for that temperature? Or will the camera automatically choose the right profile based on the temperature?

5. While shooting, is there an indicator that will tell you that the current blackshade profile is not appropriate for your current shooting conditions? and that your image has unnecessary noise? I know your T/E are supposed to be green at all times for temperature and exposure. Is THIS your indicator for that; telling you that you have inappropriate blackshading settings?

​
6. (See attached picture 1) When looking in the menu, on the left side I see "In camera" and the right side I see "on media/calibration". I assume this means the blackshade profiles I created in the camera (manual and auto) show on the left and then if there was any profiles I saved on an ssd card that is inserted, it would show on the right. Is this correct? Then in the middle you have different arrows that you would use if you wanted to save and transfer profiles from in camera over to your ssd and vice versa. Is this correct or is there a different function of it?

7. When you do an autoblackshade, does it run through all the possible temperatures itself and makes the best settings for each temperature?

8. Let's say you are in the field and your T is no longer green, it's now yellow or red. What steps do you take to get it back to green? I assume put it in a cooler place and turn the fans on high before recording again? IS there something else. What about when your E is no longer green, what are the steps you take to get it back to green before continuing to shoot

9. (see attached picture 1) When going into the blackshade menu, I see 3 profiles already there, how do I know which profile to apply? They all seem similar, I assume the 38c means "apply this profile when the temp is 38 degress celsius". Why's there 3 profiles for 38c then? Or is this not the right logic?

10. What I assume is that the most recent blackshade is at the top. Once the most recent auto blackshade is created and applied, is there any reason I would need to keep the previous profiles? or can I delete them with no problem?

11. (see attached picture 2) When clicking create profile, I get the option for auto vs manual. For what situation would I ever need to choose manual blackshade? What can I get from a manual black shade that I would not get from choosing auto-blackshade?

12. (see attached picture 3) When going to manual blackshade, it tells you to choose the exposure/shutter speed you want to shade for. This makes me assume you have to create a new black shade profile for the different shutter speeds and fps that you plan to use? Is that correct? When you click auto blackshade, does it create one profile for all the shutter speeds, or does it create a profile for the current shutter speed you have the camera set to? If it's only the current shutter speed, do I need to auto blacksahde for all of the shutter speeds that I plan to use?

 

[John Marchant]

Ok - in lieu of coming to hear me tell you all this at a Reducation one day, here goes:

1. The camera only creates blackshade data when you ask it to, not when you turn it on. It automatically selects appropriate stored calibrations after that point.
You should black shade when: a) The camera has no user blackshade b) the camera warns you via a dialog that the blackshade is out of date c) when the T/E indicators cannot be brought back to green via answers below.

2. The camera uses the SSD storage to record and analyse the image for noise characteristics, either at one fixed exposure setting (user) or a variety of predefined settings (auto). You don't need to see or touch the files it writes, and the camera will not leave them in place once the process is completed.

3. The camera manages its own temperature thermostatically by default. Only if the cooling system is outpaced by environment, or if the temp is so low as to prevent warmup will your blackshade be invalid on a temperature basis. The outlying case is that you choose a non-default fan setting, after which you will be warned by the system to manage camera temperature yourself.

4. The camera will find appropriate settings automatically if you create them, whether for temperature or exposure. Temperature fluctuation after the camera is at operating tmeperature is usually indicative of an extreme environment, and consequent care should be taken.

5. T/E are your primary indications. They tell you that the currently loaded black shade closely matches exposure time and camera temperature. The only time this will mislead is if you use a factory calibration. Then the standardised blackshade information may be correct in terms of conditions, but sub optimal as it was not designed for your exact sensor.

6. You have this all under control

7. Auto black shade targets multiple exposure times, but expects a given target camera temperature.

8. If E is no longer green, wait a few moments - the black shade takes a little while to kick in. If it doesn't, for optimum quality you can do a user blackshade at the current exposure. Expect only to bump into this under extreme exposures.

If T is no longer green, (or more likely, not YET green) again, wait briefly. Either the camera will be warming to temperature, or the fans may take 1 or 2 minutes to stabilise the temperature. Look for practical reasons first - is the camera body in direct sun, has an accessory or the way you're holding the body blocked the fan exhaust. The only proper reason for the camera's internal temperature to rise beyond nominal is if you deliberately choose a quiet record mode. Expect cooldown time in that scenario, and only use when sound dept. mandate it.

9. You can have multiple user black shades, the temp indication is as you suggest. Its up to you to manage these and throw out duplicates.

10. The file name includes the date, feel free to delete old and duplicate entries.

11. Use manual for a blackshade to suit extra long ( <1/8 ) and extra fast ( > 1/2000 ) exposure times. The long exposures are the most important here.

12. As I think you get by now - auto covers all sensible shutter speeds, manual lets you cover outlying cases by hand.

 

[Tim Daust]

http://www.reduser.net/forum/showth...es-amp-Experts&highlight=blackshading+dummies

Roger - this is the best thread for you

 

[Roger Alexander]

John, thanks so much for taking the time to go through this with me! Very much appreciated!

Tim - yes I've read through that thread before this post, but as I previously stated, alot of it refers to DSMC1 manual black shading. My questions centered around the auto black shading process and how it was different in DSMC2

 

[Tim Daust]

John, thanks so much for taking the time to go through this with me! Very much appreciated!

Tim - yes I've read through that thread before this post, but as I previously stated, alot of it refers to DSMC1 manual black shading. My questions centered around the auto black shading process and how it was different in DSMC2

Yeah it seems like John did a pretty good job helping you.

Typically I run my blackshade with the 4 planned shutter speed variations I will need (if its possible to plan for, IE my goto shutter speeds for my slo mo/realtime ) in as close of a temperature match to the environment Ill be in shooting. IE if the shoot is outside I run my blackshade outside the day before around the same time of the shoot.

You're a problem solver so if the E goes RED then just creatively change what your trying to capture for that particular shot to get a green T/E. IMHO that is better than acquiring noisey footage you dont want to use anyway in your edit. Not to mention you wont waste time on set doing a blackshade.

this is based on my experience of course and im sure others out there have a better workflow and understanding of the blackshade process.

 

[Stacey Spears]

I just want to add that I think people go overboard on blackshading. I do it after every FW update and not much more. Only have done once outside of a FW update when I noticed a red pixel in the middle of my images. Black shade fixed that. And as John points out, when doing some long exposures for timelaps, I created a new BS for that.

I think people tend to blackshade way more than they need to.

 

[Kevin DeOliveira]

We've recently been shooting 4k with Weapon, and there is a noticeable difference in noise when cropped in. Still looks good, but the grain is more prevalent. Since the noise will be equally magnified on Raven (cropped sensor) I actually thinks it's way more important to black shade often. Unless you plan to de-noise in post.

 

[Daniel S]

Neat video will do the trick right? im still testing my Raven and so far i like the almost "organic" natural look of the noise vs my 5d mk3 @ iso2000

 

[Akin A]

I haven't used DSMC2 yet, but is it correct to say that "Auto Black Shade" feature could be more accurately named "Auto Black Shade Profile Selection"?

The camera is automatically selecting a profile (based on your manually initiated, black shading process), and NOT automatically running the black shading process behind the scenes, while you continue to use the camera, as the name could lead one to assume, correct?

This is what I gather from reading the above info, so if I'm wrong, let me know.

 

[Jake Wilganowski]

All auto does is make a range of different blackshades for different shutter speeds AT A GIVEN TEMPATURE, so when shooting at a given tempature you can freely change framerates and the camera will auto load the proper blackshade for that framerate/shutter

Manuel is just picking one temp and framerate/shutter and doing a single blackshade for that setting, so if you go way higher on the shutter or framerate you will be OUT of calibration

It's really not very complicated guys, auto gives you a range to work with, Manuel is a single