This is a post that I've been meaning to write for a long time but kept on putting on the back burner. The reason for that is the subject matter - it is really boring. Believe me when I say that I'd much rather be throwing paint around than thinking about f stops and gn numbers!
However, more people ask me technical questions about how I photograph my paintings than just about anything else so I figured that I'd bite the bullet and get something down on virtual paper.
This is in three parts, the first is intended for those who already own the hardware and just want a recipe i.e. the settings and who do not require the underpinning logic, the third is a deeper dive and the second falls somewhere between the two.
VERY SHORT VERSION
Use a DSLR or Mirrorless Camera
Shutter speed: Flash Synch for Camera (usually around 1/200s)
Painting on an easel, wall or table leaning against a wall.
Flash: External unit mounted on horseshoe, pointed straight up at ceiling.
Flash Setting: Manual, 1/1 or 1/2 power
Adjust the flash settings to get correct exposure.
If flash is not powerful enough raise ISO
Shoot hand held no tripod (or in-camera image stabilization for that matter) required.
Keep camera sensor parallel to the painting being photographed.
Crop, color correct etc., in Adobe Lightroom on desktop or laptop computer.
Crop sensor DSLR or Mirrorless recommended
Flash (can be third party and cheap)
Good consumer level equipment is fine
Equipment does not have to be state of the art (mine is all currently at least 8 years old).
Make sure sensor is large enough and that there are enough megapixels
Flash should be reasonably powerful but doesn't have to be capable of automatic operation (TTL) with your camera.
Everything on manual but don't panic.
RAW not jpg (always)
Don't set zoom lens at extreme ends of range
Aperture should be between f8 and f11
ISO 100 (or whatever your camera's native ISO happens to be).
Shutter speed should be whatever your camera's synch speed is (usually around 1/200)
Point the flash straight up at the ceiling.
Stand in front of painting, point the camera at it, keeping the plane of the sensor parallel to the painting, and press the shutter. Stand a further away than the minimum autofocusing distance.
If photograph is over or underexposed make adjustments with flash only - leave the camera settings where they are if possible.If your flash is maxed out though then adjust iso. Try to not go above 400 though.
I use Lightroom almost exclusively. Despite its faults it's still the most convenient and has the tools that I need.
Don't overcook the image but do use the software as an artistic tool. I will, for example, shift colors and alter contrast if it improves the image but will never push things so far that image starts to look digital or artificial.
The camera I use is a Samsung mirrorless NX1000 which is now out of production but that doesn't really matter. Any mirrorless or so-called consumer level DSLR is more than enough to get the job done. The key thing here is sensor size. You want a crop, or APS-C sensor. These sensors are about an inch on the long side and have a large enough surface area to capture the required detail with enough accuracy. I would also look for something at around 24 megapixels as this will ensure that there is enough information to print the image at a decent size.
I wouldn't recommend smartphones for photographs that have to be enlarged a lot, i.e. for printing. The megapixel count is usually high enough but the sensor size is just too small. Phones compensate for this by doing lots of software magic after the fact - something that works well for scenery and portraiture but not for accurate renderings of artworks. There are cameras with sensors that are larger than a smartphone's but smaller than a crop sensor that would be OK but offer no real advantages.
If a smartphone is the only available option take the painting outside, either on an overcast but bright day. Do not use the smartphone flash or try to shoot in direct sunlight. If overcast days don't happen where you are find somewhere in shade - not under trees though as these will give a dappled light and a green cast - definitely not desirable. Getting enough light onto the subject to really is the key here. With flagship models it may even be possible to produce a decent large print and if that isn't the case now I suspect it will be in the not-to-distant future.
The zoom lens, (often referred to as kit lens) supplied with most consumer cameras should be fine. An alternative to a zoom lens is a prime or fixed focal length. The advantage primes with is that even the cheap ones tend to be very sharp but the disadvantage is the lack of flexibility. Not being able to zoom out in a small room could be a big handicap, especially if you tend to work large. For reference a 50mm lens requires a camera to painting distance of around 10 feet to fit in a 3ft x 2ft artwork. In other words, if you work large then a zoom of say 18-55mm would be a better bet. Fortunately this is a very common kit lens size. I use a 50-200mm lens as my workhorse because my paintings tend to be small but I do have an 18-55mm lens for larger works and for very large ones (i.e. the size of a whole wall) I have a 11-17mm.
If you need to buy a lens the following information could save you some money. Image Stabilization (sometimes called Vibration Reduction) is not necessary and the lens can be slow More about both of these factors further down under 'settings'.
Don't go out and buy the one that your camera manufacturer recommends unless you intend doing a lot of flash photography. The reason for this is that the recommended flash will communicate with the camera in ways that border on magical but will make absolutely no difference to what you need to do. A camera manufacturers flash is likely to set you back around $500 while one that will get the job done just as well will cost around $50.
The maximum output is, however, an important consideration here and I would look for something with a GN(a measure of how much light the flash puts out at its maximum setting) of at least 58 and ideally a little higher.
Also, don't use your camera's built in flash - it points in the wrong direction and is probably not powerful enough.
I'll try to keep this as non-technical as possible but there will be moments of failure. Please add a comment if clarification is required and I'll reply and edit this post accordingly.
ISO: Native (Usually 100)
Shutterspeed: Flash sync speed (Usually 1/200. Note this is camera specific and the same regardless of flash unit attached),
Aperture (the size of the hole that the light comes through):
f8-f11 (f11 is better but will require a more powerful flash)
For clarification, a bigger number indicates a smaller hole. We want a small hole for the following reasons:
a) Bigger depth of field which means that the whole image has a better chance of being in sharp focus.
b) No ambient light reaches the sensor, just the light from the flash. This allows for complete consistency once you have worked out your ideal settings. In other words it won't matter whether you are shooting in the middle of the night or at noon with sun blazing in through the windows, the required settings will remain the same. This basically turns the camera into a point and shoot. I don't only photograph finished work but like to record all parts of a process and not having to reset the camera and flash every time is a huge bonus. There is a minor caveat here and that is that the required exposure will be different for light or dark paintings but this should be accounted for by making adjustments to the flash not the camera settings where possible.
Now for a bit about focal lengths. The focal length determines how much of a scene is in frame at a given distance. A prime or fixed lens has a single focal length whereas a zoom covers a range of focal distances. A prime will leave you with little option regarding where to stand. There will only be one place where the painting occupies all of the frame. A zoom gives options and therefore requires a little more thought. The rules of thumb are to try to avoid using the extremes of the zoom capability and to stand a little further back than the minimum autofocus distance. Zooms tend to be sharpest in their midrange and autofocus can become hit or miss when used at the edge of its range. If your lens says it focuses from three feet say, then try to stand at least five feet from the painting.
Always have the flash set on manual as opposed to automatic. Use this setting as the variable for the whole system. Ideally you will not have to touch the settings on the camera. Bounce the flash off the ceiling. Never fire it straight at the painting. This gives a much more pleasing light and no hard shadows from any texture in the work. It also results in the least amount of glare. On the topic of glare always try to photograph your painting before applying any sort of varnish or finishing coat. Also, try to get your photograph before the art is framed as the top of the frame will cast a shadow on the top the the painting. This shadow can be removed in an editor like Lightroom but it is a bit of a pain. Glare is much harder to deal with in post production.
While it is always best to get as close as possible to perfection in camera there will always be some editing required. Cropping to the size of the painting is almost always required but there are other optional changes that can be beneficial. A little sharpening and noise reduction works well as do minor color, exposure and contrast corrections. I would always be wary of overcorrecting though - too much saturation or contrast can make an image look artificial and computer created.
I use Adobe Lightroom because I am used to it and it offers a couple of tools that I find invaluable. One of these is a perspective correction tool that allows for the straightening of a painting even if the camera sensor was not parallel to the painting.
While I think that overcooking an image in the editing part of the process is a bad idea I am not against tweaking things such as color hue for creative effect or to combat camera sensor deficiency. For example I often push yellows a little away from green and toward orange and my oranges slightly toward red. I will also do so some digital cross processing to put a little orange in the shadows and blue in the highlights, again I don't ramp everything up to eleven, a little goes a long way.
I do regard the photography and subsequent editing as part of the artistic process and not just an add on and I think that this helps me a lot. I find that what I see on the screen by virtue of simply adjusting a few sliders feeds back into my painting and often causes my working palette to change.
Initially, it may take some trial and error to get the perfect setup but any time invested will more than pay for itself over time. The one thing you don't want to be doing is reinventing the wheel every time you need a photograph of a painting. In the last year I have shot well over a thousand images of both finished paintings and works in progress and have had to find a fast, easy way of doing this to a high standards.
Quick note for my patrons: I'll have some more high resolution images available by Sunday and will bundle all of the March downloads into one zip file within the next few days.