The Cinemartin NEXT part 2.

June 1, 2015 alisterchapman Leave a comment

If you haven’t seen part one, first jump over to part one, then take a look at the video below.

The Cinemartin NEXT has some really great connectivity even though it’s very small. When you are using it on location you can use just the built in high brightness touch screen, but as soon as you get back to base you can expand the display to one or two external monitors using the display port connectors. Expanding the desktop over a couple of external monitors turns the NEXT into a fully featured workstation that is perfect for editing, grading or transcoding functions.

In addition to the display port outputs for the computer desktop you can also connect a professional video monitor to the HDMI or SDI outputs of the integral Decklink video card. If you are working in SD you can even output via component or composite video. So with 3 monitors, two showing your desktop and one showing your video output you have a plenty of screen real estate to work on.

With this type of setup you will want to add an external keyboard and mouse. The touch screen display is great on location, but for more intensive edit, DiT or encoding operations a proper mouse and keyboard is much better. As there are plenty of USB3 ports you could just use a USB keyboard and mouse. Or you can plug in a tiny bluetooth adapter and connect your mouse and keyboard wirelessly.

As the NEXT is a computer you can run whichever edit application you prefer, or pretty much any application of any type that you wish. There is plenty of processing power (up to generation 5 i7 muticore) and lots of memory (up to 32GB) so it will run almost anything you want to throw at it, including OS-X.

Running Adobe Premiere on the NEXT is easy.

When I tested it running Adobe Premier CC the editing experience was just as slick and smooth as my dedicated edit work station. I could edit the 4K uncompressed material recorded directly on to the NEXT’s internal SSD with ease. Even transitions such as dissolves played back at 4K without jumps or skipping. The Decklink card gives you a direct monitor output connection from the Premiere Timeline at up to 4K. This should also work with the majority other other edit applications as the Decklink cards are pretty much the industry standard these days.

By using the USB3 ports you can expand the NEXT’s storage or bring in material from other sources with ease.

One very neat way to expand it’s storage is with one of Samsungs T1 micro USB3 SSD’s. These drives really are tiny, not much bigger than an SxS card, but while small they do also offer great performance and can be used to record and playback 4K material. With 4 USB3 ports you could add up to 4TB of T1 storage or connect the NEXT to an external raid array for bigger projects.

Once you have done your editing you can play out your projects timeline direct from the NEXT. The integral Decklink hardware will play out 4K, HD and SD direct from Adobe Premiere’s timeline or via the included Decklink Studio player software.

Built in hardware based down conversion.

In addition you can use the boards hardware downconverter to playback 4K content in HD, or HD content in SD. This is really useful if your working with 4K material but only have an HD monitor. The hardware based down conversion is much better than trying to re-scale from 4K to HD within Premiere. By attaching a breakout cable to the Decklink card you can get a full range of inputs and outputs including standard definition composite, component and Y/C (S-video).

The ability to play out and edit directly from the timeline will be great for news and other fast turnaround projects. By shooting directly on to the NEXT, editing directly with the NEXT and then playing out directly from the NEXT you cut out all those normal transfer, transcode and rendering steps that can really slow down your workflow.

If you do need to transcode your footage then the NEXT has a built in background encoder that can transcode to a number of ProRes and H265 presets very quickly while you are getting on with other work. Its hard to find decent H265 encoders at the moment. The Cinemartin Live application included with the NEXT is really very good and produces remarkably compact files with great image quality. H265 is great for sending material via ftp to broadcasters for breaking news stories. The compact file size means your transfer will happen quickly. Need to stream or ftp wirelessly? Well that’s no problem as you can simply insert whatever type of wireless modem you need into one of the USB3 slots, whether that’s a wifi dongle or 4G/LTE dongle. For wired connections there are already a pair of Gigabit Ethernet ports built in to the NEXT.

Just some of the recording options on the Cinemartin NEXT.

In terms of image quality, well the NEXT uses a Decklink 4K input and output card. These cards are used in high end edit systems (it’s what I have in my workstation). The uncompressed video is just that: Uncompressed. You can even record full RGB 444 in 4K at up to 60fps with the higher end models. This means that there are absolutely no compression artefacts. What comes out of the camera is what’s recorded, with no loss. So the playback is identical to the camera output. This means you are getting the absolute best quality recordings possible, better in most cases than the cameras internal recordings. There are some side by side examples in the video at the top of the page of just how video compression can really degrade the quality of a recording.

Uncompressed video like this is wonderful for green screen or chroma key where compression artefacts can really degrade the quality of the key. Its also fantastic for shooting in log as you retain every possible bit of data in the log recording so you will have the best possible master recording to take into the grade. And don’t forget you can even do the grade using the NEXT. Adobe SpeedGrade runs very well on it. If you don’t need uncompressed then there is also the option to record compressed using very high quality MJPEG as well as a DPX recording option. If you want ProRes than that isn’t a problem as you can shoot in uncompressed and then while shooting use the Cinemartin Live application to transcode your uncompressed footage to ProRes in the background. It’s recommended that if you want to do this you opt for one of the i5 or i7 processor models to deliver the fastest encoding performance.

Of course video is really dull without sound. In the sound department the next won’t disappoint either. You can record and play back up to 8 channels of audio embedded in the HDMI or HDSDI video stream or you can use the separate AES/EBU digital inputs or up to 4 channels of analog audio in and out (depending on model) that can be connected via the decklink cards breakout cable.

If you are shooting in 3D then a single NEXT can take the HDSDI outputs of both the left and right cameras at the same time and record both in a single multiplexed video stream. This saves the often time consuming chore of re-syncing and pairing discreet recordings and keeps everything together in a perfectly synced single file. I really wish the NEXT had been around 4 years ago when I was still shooting a lot of 3D.

The power consumption is very low at around 30W. This means you can easily run it from a D-Tap connection on your camera or existing battery system. If you need a stand-alone battery system then you can use highly affordable external laptop batteries batteries that start at about $150 and will typically power the NEXT for between 3 and 5 hours.

The NEXT isn’t going to be a device for everyone. It is a bit bigger than some of the other recorders on the market. But it can do so much more than just record. As already mentioned you can use it to edit, grade, encode and stream. You can even use it to check your emails. You could use it as a video player for interactive installations, use it as a high end 4K media server. A recorder with multi-channel audio capabilities for concerts or other similar events. There really isn’t anything else quite like it on the market. Price wise it is very competitive compared to other 4K capable recorders starting at around $2200 USD for a basic 4K HDMI capable unit going up to around $6000 for the very highest specified unit. But don’t forget, this isn’t just a recorder, it can do so much more and cuts out the need to transfer material from cards to the computer for editing. So do take a look at the wealth of information about the NEXT available on the Cinemartin web site.

Uncategorized

PMW-F55 and PMW-F5 Firmware Version 6 now available.

June 1, 2015 alisterchapman Leave a comment

So here it is. Firmware version 6 for the PMW-F55 and PMW-F5.

http://community.sony.com/t5/F5-F55/NEW-Version-6-Firmware-F5-and-F55/m-p/506807#U506807

This adds the ProRes capability to those with the optional codec upgrade card. It also brings User 3D LUT’s to Slog2 and a few other bug fixes.

PXW-FS7, Review, Uncategorized

My PXW-FS7. Add-ons and configuration.

May 31, 2015 alisterchapman 14 Comments

I though I would share a few pictures of how I like to configure my Sony PXW-FS7.

I mainly use the FS7 for run and gun type shooting, so portability and ease of use is very important.

So here is the overall package:

One of the key parts to the whole rig is the Vocas base plate. Vocas offer a couple of different base plate options. The one I have is shaped to follow the contour of the base of the camera so keeps the center of gravity as low as possible. It’s also compatible with a standard VCT quick release tripod plate so a great way to get the camera on and off a tripod really quickly. The shoulder pad slides forwards and back so you can adjust the balance point a bit, but the shape of the FS7 does tend to mean that the rig will be a bit front heavy (unless you add rear rods and a battery as I do). Attached to the left side of the base plate are a couple of Vocas lightweight arm sections and a beautiful wooden hand grip. I can’t recommend the Vocas hand grips enough, when you are out shooting all day a comfy hand grip makes a big difference.

A really weak area of the Sony FS7 is the viewfinder attachment. Fortunately Vocas have a solution for that.

The Vocas FS7 viewfinder arm can be attached to the existing Sony 15mm rod that the original viewfinder arm attaches to, or it can be attached to a supplementary 15mm rod attached to the Vocas top cheese plate (you’ll see that in a picture further down the page). The great thing about this Vocas VF arm is that you can slide the viewfinder fore and aft or move it up and down without the viewfinder drooping as it does with the original mount. This helps maintain a level horizon on the viewfinder screen which is really important when shooting handheld. A droopy viewfinder can easily lead to shots that are tilted over as it is very easy to miss that the horizon in the viewfinder isn’t level.

On the right side of my FS7 you can see that I have a Shape hand grip arm. Vocas make a very similar one if you want to keep everything one brand, but I got given this shape arm to test while I was in Canada. It has a big red quick adjust button that allows you to alter the angle of the arm as well as a single thumb screw to alter the length. This is so much nicer than the standard Sony arm. In addition the combination of the wider Vocas base plate and Shape arm means that the remote handgrip arm now no longer fouls the tripod head in the same way that the standard Sony one does. The microphone mount is one from Alphatron that attaches to a 15mm rod and the microphone is a Sony stereo microphone (from one of my F3 cameras). The tripod shown in these pictures is a Miller Compass 15 head on a set of their really incredible “Solo” carbon fiber legs. This is a very light weight system, great for travelling, yet still stable and robust. The legs can extend to well above head hight and collapse down to just a few inches above the ground.

On the top of the camera you can see my trusty Convergent Design Odyssey 7Q monitor/ProRes recorder as well as an Alphatron Tristar 4 LED light.

While the Tristar 4 doesn’t look all that different from many of the other LED lights on the market it is quite a remarkable little light. For a start the quality of the light output really is quite exceptional. When tested by Alan Roberts it scored 86 on the TLC Index. TLCI index measures the spectral performance of a light in a way that determines how it will perform for video and television applications. This takes into account things like green shifts and other color issues common with LED and fluorescent lights that CRI does not measure very well. A score of 86 is very good, especially for a compact light at this price point. It’s called a TriStar because each of the LED’s actually has 3 emitters which helps provide a very uniform yet high power light output.

Another great thing about the Tristar 4 is it’s build quality. This light is built to last. It’s is very tough and can be dropped on a concrete floor or bashed into a door frame while walking through it with the camera on your shoulder without breaking. The Tristar 4 has variable intensity and color balance and can be powered from standard Sony NP-F type batteries. The light comes with a D-Tap cable and a ball head for camera mounting. I choose to power it from a D-Tap outlet on my PAG battery system.

I love the PAGLINK battery system! I have them mounted on a V-Mount plate attached to a pair of 15mm rails on the rear of the camera. This helps balance the camera on my shoulder much better. If you are using the FS7 extension unit then the PAGLink batteries will go directly on to this. I’ll be writing more about these innovative batteries soon, but the key feature is the ability to stack several batteries together to produce a higher capacity pack or to charge several batteries at once with a single charger. Each battery has a sticker indicating that it complies with current regulations for hand carrying Li-Ion batts on aircraft and a copy of the test certificate is included with each pack. If you need to power accessories such as the Tristar 4 video light or the Convergent Design Odyssey then you can clip on the PAGLink Powerhub which can be configured with up to 4 D-Tap or Hirose connectors. It can also charge your phone via a USB socket on the bottom.

For lenses I am typically using either a Commlite EF adapter or Metabones Speedbooster EF adapter. I have a large selection of EF Mount lenses from Sigma, Tamron and Samyang.

As most of these lenses are quite small I don’t need a giant matte box. So to keep the weight down I use a Vocas MB215 matte box. This has a single rotating tray for up to 4×6 filters plus a clever holder for a 4×4 filter in the front of the hood. One thing I really like is the 16×9 shaped aperture at the front of the Matte Box. This really helps reduce flare in the lens without having a big flag or barn doors which often get in the way when shooting run and gun. You can attach the matte box directly to the lens as a clip-on, but I prefer to mount it on rails. The rails at the front of the camera help protect the lens from bumps and knocks when putting it down on the ground.

The final part to show you is the Vocas top cheese plate. If you look at the front of the cheese plate you will also see the additional mounting place for an alternate viewfinder attachment rod. The nice thing about this cheese plate is that you can install it without removing the handle, so you retain the cameras GPS and hotshoe functions. There are plenty of mounting points for accessories with both 1/4″ and 3/8″ threaded holes. The underside of the cheese plate is mostly hollow so it adds very little weight.

So there you have it. A quick run down of what my PXW-FS7 like to wear when it’s going out on a date.

Don’t forget I still have one place left for my wild weather workshop in June. Click here for details.

Everything Else

The cost of being a freelancer.

May 19, 2015 alisterchapman 2 Comments

You spend weeks juggling dates, turn down other significant jobs to work with an important client to keep them happy. Book flights, pay out lots on advanced expenses for a 10 day job and all is set. Then at the last minute the 10 day job becomes a 4 day job, new flights have to be booked etc and all your planning goes out the window. I don’t think some clients realise how much it can cost a freelancer to have work cut or cancelled. It’s not just the loss of earnings from the cut job but also the loss of business with other clients and other additional costs. It takes time to re-book flights and hotels etc.

Earlier in the year the plan had been: Fly long haul from London to Singapore (client A), fly from Singapore to LA for a job for client B, then while in the US go storm chasing, fly home. One round trip ticket, 6 days for client A, 4 days for client B no dead time. Cost of ticket split between clients. Everyone happy.

But client A decides they can get better value for money by extending my trip, so I work with client A to make that happen, but this means I have to cancel client B. So now I’m all set to fly to Singapore for 9 days for client A. Then fly home. Then fly to USA for storm chasing a few days later. This involves the expense of two round trip long haul tickets. Client A happy, client B not so happy (but understands the situation). Everything is confirmed, set in stone. Flights are booked, hotels booked. Dates blocked out in my diary so when people try to book me on those dates I have to turn them away. June is always very busy for me.

But now last minute, client A has decided they no longer want to extend the trip, so I will fly home 5 days earlier than booked (IF I can get flights). There is now dead time in between Singapore and Storm chasing that I cannot fill, time when I could have been working for client B or client C, D and E who were turned away because I thought I was going to be busy.

What’s really annoying is that Client A KNEW that I was going to have to cancel another important job to help them with the extra days in Singapore.

So all in all I’ve gone from 10 days of work to 4, I’m having to pay out for long haul flights that I could have got covered by Client B, all because I decided to work with client A to help them out. When I quoted client A for the 10 day job I gave them a 10 day discounted rate. Now they have asked me to send in a new quote for the job and have indicated they are expecting the same 10 day rate when now the job is only 4 days!

Not only all that but I used an upgrade voucher that took a year to earn on the original Singapore flight bookings, but as it’s so late in the day now I will loose that voucher when I re-book, and there is still the big question as to whether I can actually get seats and how much extra they will cost booking just two weeks ahead instead of two months ahead.

Pissed off. Glad I got that off my chest.

Review, Uncategorized

And now for something completely different: The Cinemartin NEXT (part1).

May 15, 2015 alisterchapman Leave a comment

So many of us will have used an external video recorder before and I’m sure everyone reading this has used a computer at some point. The Cinemartin NEXT is an interesting fusion of a highly portable video recorder with a super compact high end computer. Designed to go on the back of a camera the NEXT can record in beautiful uncompressed 4K 444 RGB in 10 bit at up to 30fps with an update/upgrade coming later that will allow 4K at up to 60fps via dual 6G HDSDI.

It can also record compressed and all the way down to SD resolution. But what makes the NEXT different is that it is also a very powerful PC. The sample unit I had was running windows but you can also install the majority of operating systems on it. There are some clever tools installed as standard including the capture applications and a very clever background renderer that will transcode whatever it is you are shooting to ProRes or H265. Internal storage goes all the way up to 1TB and it’s very, very fast. Memory up to 32GB.

With so much computing power on tap you can do all kinds of things. For a fast turn around job like news you can shoot directly on to the unit and then edit the footage as soon as you have finished shooting. There’s no need to transfer footage from the camera to the NEXT, it’s already on there. It can run pretty much any edit software, I used Premiere CC and editing on it was quick and easy. As it has a direct HDSDI output (as well as 4K ready HDMI outputs) you don’t even need to render out your finished edit to play it back. In most cases you could cut your news story and play it out directly from the timeline to the uplink truck. If you don’t have an uplink truck then being a computer you can render out your story as a file to upload over the internet.

There are 4 USB3 connectors and 2 ethernet connectors so you can connect to the internet either directly via ethernet or by using a wifi or 3G/4G wireless modem.

Power consumption is a very modest 15 to 29w so it will happily run of a D-Tap from your camera batteries for 3 or 4 hours. If your in a hotel room or studio you can plug in up to 2 external computer monitors (as well as an HDSDI/HDMI monitor) to expand your desktop beyond the built in high brightness touch screen display.

In the next installment I’ll take an even more in depth look at the NEXT from Cinemartin. Including some image quality comparisons.

Uncategorized

Storm Chasing and Film Making Workshop, 1 place left!

May 6, 2015 alisterchapman Leave a comment

Me shooting a tornado with the PMW-F5 and AXS-R5 on my Miller Solo tripod.

As usual I am running a combined film making workshop and tornado chasing tour. This year the trip runs from June 16th to June 25th. There is one place still open if anyone is interested.

What do you get? For a start over a week to pick my brain and learn about shooting run and gun. I will be shooting with a PXW-FS7, but you are welcome to bring whatever camera you wish. As there are only 3 guests on this trip you can be assured of plenty of one to one time.

The trip will start and end in Denver, Colorado. Where we will go in between depends on the weather. Each day I will make a detailed weather forecast and we will go to the area most likely to produce severe storms. Do note that I do not wish to get as close as possible to a tornado. I want to get photogenic footage of the storms and sometimes this means hanging back a little to find the best position taking in to account light and the motion of the storm. It should be an exciting and adventurous experience, but I am not doing this as a thrill seeking event and I don’t wish to put myself or anyone else in danger.

You can expect to see impressive Supercell thunderstorms that can produce incredible lightning displays, giant hail and damaging straight line winds. If we are luck we may even see a tornado or two. We may spend a lot of time in the car, last year we drove over 1,300 miles in 10 days. 300 to 400 miles a day is not uncommon, sometimes a lot more. In June the storm systems tend to move slowly giving some of the best video opportunities. We should end up in the Northern Great Plains, so Colorado, Nebraska, Montana and South Dakota are normal, but we could also end up down in Texas, Oklahoma and Kansas.

The cost is $1,500 USD plus hotels at cost (allow up to $1,500 for hotels). For more details please drop me a message using the contact form.

PMW-F55, PXW-FS7, Scene Files and Luts

WYSIWYG LUT’s to play with.

May 6, 2015 alisterchapman 5 Comments

Here are a couple of high dynamic range WYSIWYG LUTs to play with. These are for the F5/F55/FS7. The camera should be set to SGamut3.cine/S-log3 and the EI should be set to the base EI (2000EI F5/F55 and 1250 EI on the F55).

WYS-ACALW1 will give almost the full dynamic range of the camera with lots of highlight roll off. It’s created to capture an extremely large dynamic range to help cope with very bright scenes such as sunny exteriors. Skin tones should be around 55-65% for the best results so zebras set to around 60%.

WYS-ACHGC1 will give a 12.5 stop dynamic range. It has more contrast than ALW1 but a bit less dynamic range. The colour palette is based on a Canon type look. Skin tones should be around 60-70% so zebras set around 65%.

Let me know what you think.

Alisters-WYSIWYG-LUTS1

If you find the LUT’S useful, please consider buying me a beer or a coffee.

A7, PXW-FS7, Scene Files and Luts

S-Log2 to Canon LUT’s for the FS7/F5/F55/A7s

April 28, 2015 alisterchapman 3 Comments

More LUT’s for you to play with!

These LUT’s are primarily designed for the PMW-F5 and PXW-FS7 but they should also work with the PMW-F55 and A7s. You need to shoot in SGamut/S-Log2.

There are two types of LUT. The AC-Canon-Log versions will output Canon C-Log with Canon wide range colorspace while the AC-Canon-Look versions output using Canons wide dynamic range gamma. The C-Log versions should be a close match to a C300 shooting C-Log but the footage will need some grading as it is still log. The Canon Look versions will have better contrast and need less grading but have less dynamic range.

I don’t have a C300 to hand to test these, so I am not sure how close they are and it will vary a little depending on whether you use an FS7, A7s or F5/F55.

Click on the links below to download the LUT sets. PLEASE DO NOT HOST THESE ELSEWHERE OR DISTRIBUTE THESE ELSEWHERE OR VIA ANY MEANS OTHER THAN A LINK TO THIS PAGE.

Alisters S-log2 to Canon Luts

If you find the LUT’S useful, please consider buying me a beer or a coffee.

PMW-F55, PXW-FS7, Scene Files and Luts

LUT set for S-Log2 in Custom Mode for F5/F55/FS7

April 25, 2015 alisterchapman 3 Comments

Quite a lot of people like to use S-Log2 or S-Log3 in custom mode. I’m not a fan of this method myself, I prefer to use CineEI, but for some people using S-Log2 or S-Log3 in custom works for them. If you use S-Log2/3 in custom mode then you are working with 709 color space, so if you want to use a LUT in post you need a LUT designed for this combination. So I have created two sets, one set for S-Log2 and one set for S-Log3. The LUT’s include over and under exposure compensation and you can download them here.

NORMAL: Indicates correct Slog2 exposure, middle grey at 32% and white at 59%, for SLog3 use middle grey 41%, white 61%.

1OVER etc indicates that the LUT will compensate for footage one stop over exposed.

If you are exposing the Slog2 so that skin tones are in the 60-70% region you will most likely need to use the 2 or 3OVER LUT’s.

Click on the links below to download the LUT sets. PLEASE DO NOT HOST THESE ELSEWHERE OR DISTRIBUTE THESE ELSEWHERE OR VIA ANY MEANS OTHER THAN A LINK TO THIS PAGE.

Alisters Custom mode SLog2 to 709(800) LUTs

Alisters Custom Mode Slog3+709 to 709(800) Luts

If you find the LUT’S useful, please consider buying me a beer or a coffee.

Technology, Workflow

Why is log sometimes hard to grade?

April 24, 2015 alisterchapman 7 Comments

This comes up a lot. People shoot in log, take it in to the grading suite or worse still the edit suite, try to grade it and are less than happy with the end result. Some people really struggle to make log look good.

Why is this? Well we normally view our footage on a TV, monitor or computer screen that uses a gamma curve that follows what is known as a “power law” curve. While this isn’t actually a true linear type of curve, it most certainly is not a log curve. Rec-709 is a “power law” curve.

The key thing about this when trying to understand why log can be tricky to grade is that in the real world, the world that we see, as you go up in brightness for each stop brighter you go, there is twice as much light. A power law gamma such as 709 follows this fairly closely as each brighter stop recorded uses a lot more data than the previous. But log is quite different, to save space, log uses more or less the same amount of data for each stop, with the exception of the darkest stops that have very little data anyway. So conventional gamma = much more data per brighter stop, log gamma = same data for each stop.

So time to sit down somewhere quiet before trying to follow this crude explanation. It’s not totally scientifically accurate, but I hope you will get the point and I hope you will see why trying to grade Log in a conventional edit suite might not be the best thing to try to do.

Lets consider a scene where the brightness might be represented by some values and we record this scene with a convention gamma curve. The values recorded might go something like this, each additional stop being double the previous:

CONVENTIONAL RECORDING: 1 – 2 – 4 – 8 – 16

Then in post production we decide it’s a bit dark so we increase the gain by a factor of two to make the image brighter, the output becomes:

CONVENTIONAL AFTER 2x GAIN: 2 – 4 – 8 – 16 – 32

Notice that the number sequence uses the same numbers but they get bigger, doubling for each stop. In an image this would equate to a brighter picture with the same contrast.

Now lets consider recording in log. Log uses the same amount of data per stop, so the recorded levels for exactly the same scene would be something like this:

LOG RECORDING (“2” for each stop): 1 – 2 – 4 – 6 – 8.

If in post production if we add a factor of two gain adjustment we will get the same brightness as our uncorrected conventional recording, both reach 16, but look at the middle numbers they are different, the CONTRAST will be different.

LOG AFTER 2x GAIN: 2 – 4 – 8 – 12 – 16.

It gets even worse if we want to make the log footage as bright as the corrected conventional footage. To make the log image equally bright to the corrected conventional footage we have to use 4x gain. Then we get:

LOG AFTER 4x GAIN: 4 – 8 – 16 – 24 – 32

So now we have the same final brightness for both the corrected conventional and corrected log footage but the contrast is very different. The darks and mids from the log have become brighter than they should be, compare this to the conventional after 2x gain. The contrast has changed. This is the problem with log. Applying simple gain adjustments to log footage results in both a contrast and brightness change.

So when grading log footage you will typically need to make separate corrections to the low middle and high range. You want a lift control to adjust the blacks and deep shadows, a mid point level shift for the mid range and a high end level shift. You don’t want to use gain as not only will it make the picture brighter and darker but it will also make it more or less contrasty.

One way to grade log is to use a curve tool to alter the shape of the gamma curve, pulling down the blacks while stretching out the whites. In DaVinci Resolve you have a set of log grading color wheels as well as the conventional primary color wheels. Another way to grade log is to apply a LUT to it and then grade in more conventional 709 space, although arguably any grading is best done prior to the LUT.

Possibly the best way is to use ACES. The Academy of Motion Pictures workflow takes your footage, whether log or linear and converts it to true linear within the software. Then all corrections take place in linear space where it is much more intuitive before finally be output from ACES with a film curve applied.