First released at NAB earlier this year, the Academy Color Predictor for iOS 7 aims to let you predict and preview the color rendering capabilities of digital cameras under different lighting setups.
Great lighting is just as much science as it is art. Finding tools and resources covering the artistic side of lighting is fairly easy, finding them on the scientific side not so much. Luckily for us, there’s an incredibly bright group of people out there that think of nothing else but the physics behind light and how it relates to cinematography. They’re called The Academy’s Scientific and Technology Council, a part of the Academy of Motion Picture Arts and Sciences (the very same people who hand out those small golden statues each year that everyone seems to enjoy so much).
The Academy’s Solid State Lighting committee released a very interesting free app for the iPad (iOS 7 only) at NAB 2014 called the Academy Color Predictor (ACP). Its object is to allow cinematographers and art directors to predict and preview the color rendering capabilities of digital cameras under different lighting setups. The ACP allows you to check a camera setup with a wide variety of variables against a known reference light source, and shows you the color differences you’ll have using standard color charts on your iPad.
Here’s the issue: you have a shot that encompasses two different types of lights.
Light A is a small 1x1 foot square panel made up of hundreds of small LEDs, drawing around 40 Watts of power from a small camera battery, that you want to keep about 1-3 meters from your talent.
Light B is a giant ball of plasma 1.3 million kilometers around, putting out 3.846×1026 Watts of power from an ongoing hydrogen thermonuclear fusion reaction, that you really want to keep about 150 million kilometers or so away from your talent.
It probably wouldn’t surprise you that because of the wildly different sources of light, the spectral response of each light may be very divergent even though the color temperature (5600K) is the same. The LED panel and the Sun have different frequencies of red in their light, so they will render a red shirt in different ways. The Academy Color Predictor can show you those differences, and let you determine if this combo may pose difficulties for color correction later.
• You initially select the Camera Sensitivities Parameter. A specific camera sensor or Standard Human Observer) to set the spectral sensitivity for your imaging device. • You set the Camera Filter. A modification for any filters that you may or may not have added to the front of the camera lens. • You set the Reference Light Source. This is the light source you’re comparing to. You can select any parameter, but the most common ones would probably be Tungsten, or ISO Studio Daylight as they’re the most familiar. You can even chose theoretically perfect sources like 3200K and 5500K black bodies to see how the real world stacks up to the ideal. • You then set the Test Light Source, which has all the same choices as the Reference Light Source. You could choose HMI, or Cool Fluorescent for example. • The Light Source Filter is then added if you have one, signifying any gels that you may or may not have put over your lights. • Then you select your Target Reflectances, which are representations of different commonly used color reference charts.
The White Balance parameter allows you to simulate what would happen if you white balanced for a mix of the two lights in the same scene (Off), or if you white balanced for each light separately, for example one scene shot in two locations with different lights (On).
Then take a look at the results. The top half of each square of the color chart is the Reference Light Source, and the bottom half of each square is the Test Light source. You can now see where and what colors will be different between the two sources, and more importantly: exactly how they differ.
Each of the parameters above can be plotted in a spectral power curve in the lower part of the app. The Y axis of the curve represents the luminance value (how much of each color is in the light) vs the X axis which is the color itself. These plots can be laid on top of each other to visualize where in the color spectrum the light sources match up and where they diverge.
It’s fascinating to be able to scan through all the different lighting technologies and see what parts of the spectrum they excel at, or what parts they’re lacking altogether. It would also help in deciding which brand of light to purchase or rent. Those cheap LED’s may be tempting, but are they are missing an entire part of blue-green? Maybe a fluorescent is a better choice for this set? After playing around with this app a bit, I’ll be damned if after all the advances in lighting technology, heating up a tungsten filament still doesn’t give you the best skin-tones. It makes me want to get those power-hungry, finger-burning, explosively-bulbed monstrosities out of storage and give them a go again.
While this is an interesting app to explore color, the Academy Color Predictor is not yet exactly a production ready tool. It’s still very much a theoretical proof of concept, but a very promising one. In order to make this a magnitude more useful it definitely needs work on both scope and specificity. Scope in the amount of cameras, lights, and filters it can model; and specificity in exact model numbers. DSLR1 and DSLR2 are useful in theory, but I want to know Canon 5D mark III or Panasonic GH4 instead. Likewise Warm LED’s 1-4 need to be LightPanels, Arri, and Kinoflo, etc..
What’s the difference between shooting with fluorescents and LED lights both at 5600K? What happens to the colors when you bring a tungsten light with an 80A gel out into the daylight? Now you will know, and not only do you know in general, you will see how the light reacts based on your individual camera’s sensor! This is the promise of the Academy Color Predictor, and with a fair amount more effort from the Academy, this could be come a standard tool in everyone’s production kit.
Tags: iTunes.Color App, Photo, Photography, Photographer, Photo Assistant, PhotoAssistant, Photo Assistants
What is Shutter Count and why should you care?
Well…have you seen what’s been going on at eBay lately?
In the past month, 20 or so U.S. location, working Canon 5D Mk II bodies – the camera that really set off the DSLR video revolution – have sold for as little as $970, topping out at just under $1,600.
By comparison, a new Mark III body will set you back around $3,500, give or take.
For U.S. location Canon 7D bodies, it’s even better: over the past 3 months, transactions have closed for as little as $360, topping out just about where the 5D Mk II begins, near the $1,000 price point.
It’s a great time to buy a used camera.
Or is it a terrible time to sell a used camera?
It depends, of course, upon which side of the transaction you sit.
But three things are clear:
1) With tectonic shifts taking place in the market (from new entrants like the Panasonic GH4 and Sony A7s to the rumored replacement this September of the much-loved and venerable Canon 7D), most people know that IF they want to switch or trade up, they have a very limited time before their current gear values plummet even farther than they already have.
2) Whether you’re a buyer or a seller, a camera body with fewer shutter actuation's – all else being equal – will command a higher price than one with more, just like mileage on a used car.
3) If you can report the shutter count for the camera you’re selling, you enhance your credibility and you are likely to get to a fairer price for both parties.
Until now, Windows users were at a disadvantage compared to Mac users relying on the aptly-named ShutterCount app by DIRE Studio to do just that.
The good news: DIRE has now released a Windows version, available for the same $2.99.
Note that ShutterCount – in either version — does NOT tell you how many hours of video have been shot.
ShutterCount displays the number of shutter actuations (the shutter count) of your Canon EOS digital camera. The shutter count is read directly from a USB-connected camera, and thus provides accurate numbers that are not attainable with simple EXIF-based methods.
With ShutterCount you can easily check whether a newly purchased camera is really new, or check how heavily used a pre-owned item is. And you can save a trip to a Canon Service Center by doing the reading for yourself.
The app provides unlimited readings for an unlimited number of cameras, so you can freely track actual camera usage. Even if you work for a rental house or just lend a camera to a friend.
ShutterCount only displays the shutter count for still photos - video clips recorded are not included in the number. For a separate mirror movement reading (that includes videos) you should consult an authorized Canon Service Center.
History logging allows you to track camera usage. Logs are stored in CSV format that can be imported into Apple's Numbers or Microsoft Excel for further processing. History logging is not available on Windows.
Note: for the best compatibility with your camera it is recommended to upgrade the camera's firmware to the latest available version.
WiFi on the EOS 6D and 70D must be turned off as it blocks the USB port when turned on!
ShutterCount is certified to work with all of the cameras listed above, using their latest firmware revision.
Please quit all applications that might connect to your camera (e.g. Canon EOS Utility, Capture One, Adobe Photoshop Lightroom) before launching ShutterCount.
Questions? Problems? Check out the ShutterCount FAQ or contact our support!
More information at the ShutterCount Webpage
Isn’t it worth $2.99 to find out your camera’s shutter count?
(cover photo credit: snap from DIRE Studio)
Tags: Photo, PhotographyPhotographer, Photo Assistant
Finlay someone better able to express what I've been saying for 25 years.
You are not a storyteller - Stefan Sagmeister @ FITC from FITC on Vimeo.
Tags: Photo, Photography, Photographer, Photo Studio, Photo Assistant, Photo Assistants, Photoasssistants
SHOWstudio: Evening In Space - Daphne Guinness / David LaChapelle / Tony Visconti from SHOWstudio on Vimeo.
Daphne Guinness consolidates her move into music with a theatrical, mesmerising new music video directed by acclaimed image-maker David LaChapelle. Evening in Space was produced by Tony Visconti and is the first single from Guinness' upcoming debut album, which is billed for release in September 2014. The video features custom fashion by many of Guinness' favourite houses, including Iris van Herpen and Noritaka Tatehana, alongside pieces from her own celebrated clothing collection.
Song Writing and Performance: Daphne Guinness Music Production: Tony Visconti Video Direction: David LaChapelle
Tags: Daphne Guinness, David LaChapelle, Tony Visconti, Photo, Photography, Phtographer, Director, Photo Assistant, Photo Assistants, PhotoAssistants, Photo Studio
A federal judge has upheld a $1.2 million jury award in favor of photographer Daniel Morel, after determining that there was sufficient evidence presented at the trial last year to support the verdict.
Morel won $1.2 million in damages after a federal jury determined that Getty and AFP willfully violated his copyrights by uploading eight of his exclusive news images of the 2010 Haiti earthquake, and distributing them without his permission. The award also included an additional $20,000 damages for violations of the Digital Millennium Copyright Act.
Getty and AFP had appealed the $1.2 million award on the grounds that there was not enough evidence presented at the trial to establish willful copyright infringement. They had asked the court to vacate the jury’s finding of willful infringement, reduce the award to Morel, or grant a new trial.
A federal judge rejected the appeal.
“There was evidence from which the jury could have concluded that the defendant’s infringement (and particularly AFP’s) was not just willful but reflected a gross disregard for the rights of copyright holders,” US District Court Judge Alison Nathan wrote in a decision handed down yesterday. She added, “In light of all the consideration that the jury was entitled to consider, [reduction] of the $1.2 million statutory damages award is not required.
“The evidence was plainly sufficient for the jury to conclude that AFP’s infringement was willful under either an actual knowledge or reckless disregard theory,” Nathan said. She said the evidence for willfulness on Getty’s part was “somewhat thin” in comparison to the evidence against AFP. But she went on to say that the evidence of Getty’s willfulness “was sufficient to support the jury’s verdict.”
Morel had uploaded his images to Twitter, offering to license them to news outlets. The images were stolen and re-distributed by another Twitter account holder. Judge Nathan cited evidence presented at trial that Vincent Amalvy, AFP’s Director of Photography for the Americas, knew or should have known that the images were actually Morel’s, and that AFP didn’t have permission to distribute them.
The evidence against Getty for willful infringement was that it left Morel’s images on its web site under a false credit for more than two weeks after AFP sent a “kill notice” telling Getty to remove the images.
The award was the maximum amount of statutory damages possible under the law.
AFP and Getty had asked the court to reduce the $1.2 million award on the grounds that it was based on a “speculative” figure of actual damages amounting to $275,000 in lost sales. Judge Nathan said that on the basis of actual downloads (1,000 or more) of the image and sale prices, the actual damage estimate was reasonable. But she went on to say that juries aren’t required in any case to base statutory awards on actual damage estimates.
She also rejected arguments that the $1.2 million statutory award was “instinsically excessive.” Noting that courts defer to the prerogative of juries to set damage awards and rarely set them aside unless they “shock the judicial conscience and constitute of denial of justice,” Nathan said AFP’s actions in particular could be seen as “gross disregard for the rights of copyright holders” and let the jury award stand.
At the same time, Nathan upheld a $10,000 jury award against AFP for Digital Millennium Copyright Act (DMCA) violations, while vacating a $10,000 award for DMCA violations against Getty.
The DMCA makes it unlawful to intentionally remove or alter copyright management information, or to knowingly provide or distribute false copyright management information with intent to conceal infringement.
Evidence presented at trial showed that Vincent Amalvy, the AFP Director of Photography, knew that Morel’s images were falsely credited to another Twitter user, but distributed the pictures with the false credit anyway, Judge Nathan wrote in her decision.
Getty violated the DMCA by continuing to distribute the images under a false credit, after receiving notice from AFP to remove the images, the judge said. But Getty was not liable under a DMCA provision for distributing the images with knowledge before the fact that the image credits had been illegally altered.
Willkie Farr & Gallagher LLP press release below:
Court Upholds Landmark Jury Verdict for Willkie Client, Photojournalist Daniel Morel
New York, NY (August 14, 2014) — U.S. District Judge Alison Nathan of the U.S. District Court for the Southern District of New York yesterday issued a Decision and Order upholding the jury’s verdict that Agence France-Presse and Getty Images (US) Inc. must pay $1.22 million for willfully infringing photojournalist Daniel Morel’s copyrights in his award-winning images of the 2010 earthquake in Haiti.
In the Decision, the Court rejected defendants’ argument that there was insufficient evidence to support the jury’s finding that the defendants acted willfully when they wrongfully misappropriated and transmitted Mr. Morel’s photographs to over 1,000 of their subscribers and licensees. The Court also left intact the jury’s award of the maximum statutory damages available under the Copyright Act. The Court held: “There was evidence from which the jury could have concluded that Defendants’ infringement (and particularly AFP’s) was not just willful but reflected a gross disregard for the rights of copyright holders.” After learning of the Decision, Mr. Morel said, “I am grateful that Judge Nathan recognizes the value of a photojournalist’s work and that she is holding AFP and Getty Images fully responsible for what they did to me. I hope no other photojournalist will have to go through a similar ordeal.”
The Willkie team is led by partner Joseph Baio in the firm’s New York Office. ***************************************************** Willkie Farr & Gallagher LLP is an international law firm of over 600 attorneys with offices in New York, Washington, Paris, London, Milan, Rome, Frankfurt and Brussels. The firm is headquartered in New York City at 787 Seventh Avenue. Tel: 212.728.8000.
Tags: Copyright, Morel v. AFP, Verdict, Getty, Twitter, Daniel Morel, Photo, Photography, Photographer, Photo Assistant, Photo Assistants, PhotoAssistant
Our list of the 10 most important things you need to know about Magic Lantern (though not necessarily in order).
This was the primary reason I first tried Magic Lantern with my Canon EOS 5D Mark II.
No newsflash: it’s critical for filmmakers to be able to monitor audio in real time. How else are you going to know that the wireless lav mics you worked so hard to set right have just gotten a burst of static from a passing truck and you need to reshoot?
Magic Lantern allows you to visually monitor audio levels in real-time. While a whole not-so-cottage industry has arisen from the fact that audio is not Canon’s strong suit (Zoom H4n, anyone? JuicedLink, perhaps?), it sure makes things much easier, less expensive and less bulky when you can feed an audio signal directly into the camera and know what’s actually happening with VU meters.
Even more magical, and another glaring omission on too many Canon DSLR’s: no headphone jack. With Magic Lantern installed, not only can you SEE what’s coming across from your audio source – you can HEAR it, thanks to ML wizardry which can turn either the USB port or the remote port into a headphone jack (NB: you’ll need a special cable like this one to adapt the signal out to a regular pair of headphones like the Bose QuietComfort 15 – or risk damaging the ‘phones).
Pro cameras have them; the Panasonic GH4 and Sony A7s have them; but most Canons don’t. These are a simple set of visual overlays that show you – without having to put on your bifocals or hope your EVF/Screen is properly calibrated – whether you are blowing out your highlights or crushing your blacks.
What was that about bifocals? Even if you have 20/20 vision, achieving critical focus on Canon DSLR’s is notoriously difficult (before I bought an external EVF, I thought it was me – it wasn’t). Focus peaking is another simple visual indicator to help you determine when the thing you want in focus IS in focus. Truly a gift from the Magic Lantern community.
A bit of a surprise when I found this: you can use Magic Lantern to set two different focus points and then let the camera move between them – it’s a software driven focus pull. Very cool feature, though not as flexible as a human being doing the actual job. And, it must be said, both the Canon EOS 70D and Canon EOS Rebel SL1 now allow you to do the same thing more easily in production-robust software.
Maybe the single most exciting feature of Magic Lantern, this allows a filmmaker to capture the full power of Canon’s sensors – and the difference in image quality, along with the ability to operate on the footage in post – is night and day compared to the H.264 output. Then again, so is the increase in storage required and the workflow necessary to bring RAW footage into an NLE, NOT in RAW’s favor. NB: RAW doesn’t work on all Canon DSLR’s, and is still very much in process.
This is a very clever way of increasing the effective dynamic range of Canon DSLR sensors. The ML community has achieved this by programming the software to identify highlights and shadows – and then to differentially set ISO in those areas (low and high, respectively) to prevent highlights from being blown out or shadows to be crushed. With this written, it is achieved at the expense of resolution in those areas (it’s halved), but the result can be stunning nonetheless.
With Magic Lantern, you don’t need an external remote or intervalometer – it’s built right into the software.
ML is an open source collaboration of truly passionate and brilliant people who wanted to get more from Canon hardware than Canon itself would allow. They’ve done an amazing job.
AND IT’S FREE!
But they are equally clear that they do not – cannot – make any claim to being error-free, nor immune from crashing your entire camera. CAVEAT EMPTOR. I’ve personally experienced successfully loading up ML on one flash card and booting into it, but unsuccessful loading it up on to a second card.
Especially with the video-centric Panasonic GH4 and Sony A7s, the marketplace has shifted under Canon’s feet. They may yet rectify this situation at Photokina this fall – but they may not. In the meantime, ML may keep you in the Canon fold for a bit longer.
I mean to take nothing away from Panasonic’s tremendous accomplishment with the GH4.
And I don’t mean to overstate the case.
But am I the only one who’s looking at the little Rebel SL1 and see that it has better autofocus than every Canon body with the exception of the 70D and can take ALL current Canon lenses; has low light sensitivity on a par with – actually slightly better than – the GH4; and weighs just 370g without battery or SD card and 492g with; and that it is thus lighter than the Panasonic GH4 similarly configured at 560g?
Of course, the GH4 has better dynamic range and color depth according to DxOMark – and a little thing called internal 4K recording, stellar EVF and more — but hey, Canon, are you listening? You could do this if you truly wanted to.
In the meantime, as I’ve written before, thank goodness we have Magic Lantern.
Tags: Magic Lantern, CanonPhoto, Photo Assisatnts, Photo Assistant, Photo Studio
Magic Lantern allows you to visually monitor audio levels in real-time. While a whole not-so-cottage industry has arisen from the fact that audio is not Canon's strong suit (Zoom H4n,JuicedLink), it sure makes things much easier, less expensive and less bulky when you can feed an audio signal directly into the camera and know what's actually happening with VU meters.
Pro cameras have them; the Panasonic GH4 and Sony A7s have them; but most Canons don't. These are a simple set of visual overlays that show you – without having to put on your bifocals or hope your EVF/Screen is properly calibrated – whether you are blowing out your highlights or crushing your blacks.
But am I the only one who’s looking at the little RebelSL1 and see that it has better autofocus than every Canon body with the exception of the 70D and can take ALL current Canon lenses; has low light sensitivity on a par with – actually slightly better than – the GH4; and weighs just 370g without battery or SD card and 492g with; and that it is thus lighter than the Panasonic GH4 similarly configured at 560g?
Manfrotto has announced a new line of backpacks and accessories, the Pro Light series. The new line includes backpacks designed for both still photographers and videographers, holsters and rain covers, all designed with an emphasis on portability and versatility. The five styles of backpacks for still photographers offer side access for another route to your gear and are priced from $220 - $310 USD/£199.95 - £249.95 GBP. See the video and press release below for more information.
Manfrotto Pro Light Bags Backpack MB PL-3N1-25 from Manfrotto on Vimeo.
Lightweight, Durable Pro Light Collection Strikes the Perfect Balance for Professionals on the Move
Upper Saddle River, N.J. (August 11, 2014) – Manfrotto, a leading global distributor of premium photo, video and lighting support products and accessories, proudly introduces its new Pro Light Bags Collection, designed for on-the-move professional photographers, videographers and advanced hobbyists. Crafted using the most innovative materials and design techniques, the Pro Light bags are the lightest carrying solutions in the Manfrotto range, while providing superior protection and ease of access.
"Manfrotto offers the most comprehensive range of premier quality carrying solutions on the market today, each of which was designed with specific users and applications in mind," said Paul Zakrzewski, Director of Marketing for Manfrotto Distribution, Inc. "The Pro Light Collection is certainly no exception in that it was created to meet the needs of professionals on the go. These bags were designed specifically for professionals who need to carry a lot of high end gear in a comfortable, highly-protective case and then have quick, easy access to all that gear at the drop of a hat."
Manfrotto's Pro Light bag line offers a comprehensive range of carrying solutions designed specifically for photographers and videographers who need to bring a considerable amount of gear on active assignments. Versatile, functional and extremely ergonomic, Manfrotto's Pro Light photo bag range features a number of intuitive, creative solutions that facilitate rapid access to equipment. The 3N1 Backpacks, for example, enable users to rotate the backpack to their chest and access their gear via the fast-opening side pocket within seconds -- without ever having to remove the bag from their body.
"Innovation is a major part of the Manfrotto DNA and the Pro Light Collection is representative of that," noted Zakrzewski. "As the needs and preferences of the photo and video communities continue to evolve, so must the equipment that we develop to support them in their work. With the addition of the Pro Light Collection to the Manfrotto family of bags, we now offer innovative, reliable carrying solutions for all skill levels, personal preferences, and imaging missions."
Pro Light bags have top wearability and ergonomic access solutions, combined with a stylish Italian design true to the Manfrotto brand. Its tough outer layer and high-resistant nylon legs provide the greatest protection to the gear inside.
Key features of Manfrotto's Pro Light bags include:
Manfrotto's Pro Light Bags Collection includes a total of 28 product SKUs, including holsters, photo backpacks, video backpacks, rolling organizers, video cases, and accessories such as element covers and camera straps. The bags are available now at retailers nationwide, and range in price from $44.00 to $550.00.
To learn more about Manfrotto's extensive range of bag options and collections, visit http://www.manfrotto.us/camera-bags-collection.
For additional information or to learn more about Manfrotto's photo and video products and accessories, visit www.manfrotto.us. Follow Manfrotto on Facebook at https://www.facebook.com/ManfrottoSoX or on Twitter @manfrotto_us.
Tags: Manfrotto, Photo, Photographer, Photography, Photo Assistant, Photo Assistants, Photographers Assistant
Lady Gaga by Robert Wilson - "Ingres"
Lady Gaga posed for nearly 6 hours to appear in Robert Wilson's video portrait, recreating Ingres' 19th century portrait of Mademoiselle Caroline Rivière. The moving portrait hung at the Louvre last year and was brought to New York's Watermill Center last month.
Tags: Robert Wilson, Lady Gaga, Living Portrait, Photo, Photography, Photographer, Photo Assistant, Photo Assistants, Photographers Assistant
Following Helmut Newtons lead and using the same publisher: TASCHEN, Annie Leibovitz publishes Her Life’s Work in a Limited Edition Book that looks strangely like the Helmut Newton book SUMO that was published nearly 15 years ago. Were the Helmut Newton presentation included it's own fold out chromed metal table; Annie's book gets a Tripod on clear plexi treatment. I gotta say that for $2500 it should really be a Gitzo Carbon Fiber Tripod.
When you’ve captured as many photographs as renowned photographer Annie Leibovitz long and storied career surly made it a difficult task to choose the best works for this publication; consider that fact that she has been Shooting for over 40 years for clients such as: Rolling Stone and Vanity Fair.
Her latest book is a $2,500, 476-page visual retrospective of her career.
CLICK IMAGES TO VIEW LARGER
Annie Leibovitz has photographed everything from politics to fashion, and Rockstars. This massive book will features her most iconic images, as well as some rare photographs. It is scheduled to be offered in two variations: a $2,500 Collector’s Edition and the $5,000 Art Edition.
Collector’s Edition is limited to 10,000 signed and numbered copies. And the Collector’s Edition willalso allow you to choose a dust-jacket for your new coffee table book, with 1 of the following images — Whoopi Goldberg (Berkeley, California, 1984), Keith Haring (New York City, 1986), David Byrne (Los Angeles, 1986), and Patti Smith (New Orleans, 1978).
If the Art Edition (which is yet to be released) is more to your liking you will receive the entire collection of dust-jackets, as well as a signed archival print of Leibovitz’s photograph of Keith Haring. This one is limited to 1,000 copies.
Regardless of what edition you choose, you’ll receive a handy little tripod, designed by Marc Newson, that will cleverly hold your book. Rather appropriate considering this baby costs as much as a pro-level DSLR.
If you have a spare $5000 and just need to have one of these books before they appear on eBay or East Village books, you can head on over to the Taschen site and your very own edition. The Art Edition is not yet released, you can still pre-order it to ensure you aren’t left out of the 1,000-copy run.
ALL IMAGES COPYRIGHT Annie Leibovitz
Tags: Annie Leibovitz, TASCHEN, Helmut Newton, Book, Fine Art, Photo, Photography, Photographer, Photo Assistant, Photo Assistants, Photographers Assistant