Hi folks,
I live outside of Philadelphia and I do not get to the Philadelphia Museum of Art frequently enough. I was able to spend a couple of hours today at the museum - if you are ever in Philadelphia, do yourself a favor and carve out some time to visit this world-class collection of paintings, sculpture, tapestry, furniture, ceramics, sliver, armor, architecture, etc. It is truly an incredible collection.
Visitors are permitted to photograph the collection, without flash. The lighting in the gallery is focused, but not very bright, to preserve the artwork. No tripods are permitted. Still, you can get some pretty decent shots if you plan ahead and shoot raw. Not that you cannot process JPEGs, but raw gives you the latitude to shoot handled, at reasonable ISO levels and achieve a shutter speed that minimizes shake, etc.
I saw a bunch of people lugging around their full-sized dSLR camera bodies and L glass, but I used my secret weapon - the Ricoh GR. This camera has a combination of features and performance that makes it ideal for a shoot like this. It is compact, fits in a pocket. It shoots raw and records to DNG natively. It has a fast (f/2.8) fixed focal length (18mm) with an effective 35mm equivalent of about 28mm. It has no anti-aliasing filter and pretty decent higher ISO performance.
I found that I was shooting at ISO 800, f/2.8 giving me a shutter speed of 1/100s. Good enough to handhold and not worry about camera shake. I shot in manual mode. Note that this example is of a piece that does not have varnish or other reflective finish - a circular polarizer might be handy if shooting s particularly reflective finish in an orientation that causes glare from the lighting.
One of my favorite artists is Jasper Johns and, lucky for me, there is a room in the PMA of Johns' work. In this processing example, I will use his painting "According to What" as an example. It is a large (approximately 16 feet wide) piece, composed of multiple panels painted in oil, with objects attached to it. The wide angle focal length makes capturing this large piece pretty straightforward - you can stand fairly close to the piece and image the entire thing in one shot. This is especially helpful if the room is crowded - you do not have to fight a bunch of people walking through you shot.
Here is the default raw conversion - for this example I used ACR - I made some adjustments to exposure and added some clarity in the actual conversion (not shown) but I left everything at default for this image to give you a sense of the lighting conditions at the exposure choice I made, balancing light, aperture, ISO and shutter speed.
Fig 1. - Default raw conversion
As you can see, this image has some issues. There is lens distortion as well as perspective distortion. Fortunately, these things can be corrected in post. The to-do list for this image, therefore, includes:
1) Exposure and contrast
2) Lens distortion
3) Perspective distortion
4) Final tonal and contrast adjustments, cropping, etc.
The Ricoh GR has no lens profile in ACR/LR. I usually do this kind of optical correction in DXO Viewpoint 2, and this PS plug-in contains the lens/camera profiles included in DXO Optics Pro (the DXO raw conversion application). In addition, Viewpoint has perspective correction tools that make correcting this image a snap.
Here is a screenshot of the DXO Viewpoint 2 interface:
Fig 2 - DXO Viewpoint 2 PS plug-in interface
The two orange arrows indicate the important parts of this correction - the first arrow is the automatic lens distortion correction for the Ricoh GR (using theDXO lens/camera profile) and the second arrow indicates the perspective correction tools. The screenshot depicts the four-point correction tool - because paintings are often rectangular, this tool is pretty straightforward to use for this correction. You place the four corners of the tool on the four corners of your distorted rectangular object in the image and the correction is applied that forces that distorted shape into a rectangle.
Note that you can use other tools, including ACR lens profiles and the various perspective correction tools in PS or LR - using ACR, the Upright tool made a mess of this image so I made manual adjustments to see how close they could get to Viewpoint. Viewpoint did a much better job, much more efficiently, but part of that was due to the lens/camera profile.
Here is the corrected result:
Fig 3. - Image after lens and perspective distortion correction
Next, tonal and contrast corrections.
Fig 4. - Screenshot of PS layers for tonal and contrast adjustments.
This is a screenshot of the layers I used in PS to do some basic tonal and contrast correction - you could probably do this in LR/ACR or raw conversion, but I do this kind of thing in PS
1) Curves layer to set black and white points.
2) Stamped copy (not really necessary - there in case you need to do cloning, cleaning up, etc.)
3) Duplicate layer, with simple rectangular mask to protect the piece. The layer is set to Screen blend mode to blow the wall close to white.
4) Local contrast addition (low opacity) using the PS plug-in called ALCE (Advanced Local Contrast Enhancer) - http://www.bigano.com …t-enhancer-photoshop.html
Once these adjustments are made, it is a matter of cropping and cleaning things up. I ended up making a mask from the blue channel to protect the piece and curving the wall background to pure white. I extended the cropped canvas to add some white space under the piece, and added text information about the piece.
Here is the final result:
Using an albeit pretty amazing point-and-shoot I was able to make a pretty decent image of this piece. Understanding how to correct for lens and perspective distortion, using a balanced exposure for the sometimes necessarily dim lighting of the gallery and knowing how you are gong to post-process shots like these frees you up to get the shot, not worrying too much about making everything perfect straight out of the camera. This is particularly useful when shooting in a cramped room or with crowds that do not understand that you are trying to make an image!
In the following posts I will share a couple more images from the gallery that I shot today, with the default raw conversion and the final.
kirk
