New Coin Photography Setup - Thoughts?

Nice pictures! I hope you are happy with your setup. I remember trying digicamcontrol with the 3200 and pretty much just gave up.

What setting are you using for Metering? If you're using Matrix or Center Weighted, the camera is using brightness outside the coin to determine exposure. The more you allow the camera to choose for settings, the more you should use Spot Metering (the only setting I ever use personally) so the camera takes all of its' exposure information from the coin itself.

That said, Exposure Compensation is a pretty powerful tool for adjustment because it has more granular settings than anything else affecting the amount of light hitting the lens.

Live View by nature should transfer the image at the same resolution the sensor sees it. Must be the implementation for your particular camera.

When you have the coin 1:1 on the sensor, evaluative metering makes sense because essentially all of the information the sensor gets is about the coin itself aside the extreme corners. With a lens like the 18-55 in use here, though, most information is coming from areas which are not coin and spot metering is in order.

What digicamcontrol appears to be doing, is only showing the liveview as it would appear on the camera lcd itself. Meaning the resolution appearing on the screen is the same as what appears on the lcd on the camera. So all I see is a tiny and somewhat grainy image on my computer. This pretty much eliminates any hope of manual focus using digicamcontrol, so I have to rely on autofocus. Even so, digicamcontrol still lets me control the settings on the camera, autofocus and instantly transfer to computer rather than it being stored on the SD card. This alone really makes a huge difference.

I've noticed that photographing raw coins is easy, I'm still having trouble with coins in slabs, because the plastic has a tendency to form what I describe as a haze on the image, at least compared to raw coins. Is there a lighting trick that would alleviate this issue?

EFLC is currently using an 18-55 lens which cannot fill the sensor with a coin; it lacks the magnification. So, spot metering where the camera meters only from the coin in the center of the sensor is appropriate. Once you reach 0.5-1:1 magnification where single coins fill the sensor, Ray's advice of Evaluative Metering is the way to go because - as he explained - you can leverage it to help with highlights. Too little space which is not coin exists to affect the shot.

I also use fully manual shutter speed. Given the lens aperture (f/8 usually) and lighting, I use the slowest speed that doesn't burn out the highlights on the coin. This usually results in a pretty dim image, especially for shiny coins. The gamma ("curves") has to be adjusted during post processing in Photoshop, to lighten up most of the image while preserving the highlights.

Is there some advantage to letting the camera adjust the shutter speed automatically?

Does the haze change as you move the lights around? And do you see the haze even if you don't see the direct reflection from your light(s) off the slab surface? If so, then you're seeing one of two things:

1)Flare from off-axis reflections hitting the lens
2)Hotspotting from your extension tubes, adapters, or bellows

Remove your camera, and look down into the tubes/bellows and see if you have lots of light reflecting off the inner surfaces. If so, you will need to flock those surfaces.

Note that I'm seeing exactly the same issue with the setup I'm putting together for mcshilling. This is the first actual setup like this I've built, and did not expect the problem.

If you're seeing something else, please post an image with the haziness so we can debug it.




An important point to note (maybe worth being TIP#2)is when using Live View, canned metering functions are disabled. You see the metering selector when you are tethered but not in Live View, but when you engage Live View the selector goes away. I'm talking Canon here...I can't remember what happens with Nikon, it's been so long but I think it's the same. So when you are in Live View, metering is done on a 'simulation' basis, ie what you see on the screen is what you get in the image, plus or minus. The metered area is the 100% magnification rectangle. If you move the rectangle from a light to a dark area, the image will lighten. Dark to light, image darkens. The tip/trick here is to move the rectangle so it includes the brightest highlights (judged visually on-screen). This will ensure those highlights are metered. Unfortunately, the metering software will still push the brightest highlights such that their "brightness" is maxed-out. If the highlights are grey color (if you're shooting untoned silver coins, for instance), this may be OK, but usually there is some color and the predominant color channel is pushed well into saturation, skewing white balance in that area. To avoid this, select -.3EV or -.5EV (or even -1EV), which will help to push the highlights down a bit and keep from oversaturating a color channel. Look at the RGB histogram and you should see this effect and know how much you need to drop the EV to compensate.