Depth of Field calculator

Most photographers know the effect of different apertures. The smaller aperture (=bigger f-value) the longer depth of field. But how long is the depth of field precisely?

I was quite surprised how much the distance from the subject affects the length of the depth of field. Let's imagine that we are taking a photo of a flower from one meter distance with 100mm f2.8 on 1.6 crop frame. Based on an online calculator the depth of field is 9.7 mm. But we want to double that because the flower is not completely sharp.

Stepping down to f5.6 gives depth of field of 19.3 mm. Now the dof is twice as long but the exposure time has become four times longer. In case of hand held photography this might be too much.

Another option is to keep aperture at f2.8 but take one step backwards so that the distance is 1.4 meters.  This will give the same depth of field as above but without the expense of longer exposure time.

How to photograph the moon

Taking a decent moon photo is not too difficult but you need to have some equipment for it. The most important one is a proper tripod or similar support for the camera. Almost as important is a decent telephoto lens. A sharp 200 mm telephoto lens is a good start for photos like this:

But even if you have the best possible gear you still need to see the moon. So, check the moon phase calendar, weather forecast and head to a dark location. Usually cities have way too much light pollution and this reduces the contrast between the sky and the moon. Find a dark area with solid ground for your tripod.

Then set up your tripod as stable as possible. Do not extend it completely unless really necessary. Select your telephoto lens with longest focal length and remove any filters you have. Even high quality filters can cause unwanted flare.

Use low ISO setting to avoid noise - ISO 100 works well. I do not pay attention to white balance as I shoot on RAW which allows more post processing options. Use mirror lock up if available and use long timer to trigger the shutter. These help to reduce camera shake and therefore improve image quality. The choice between manual and automatic focus is up to you. When using a lens without distance view the autofocus might be a better option.

Finding the right aperture for your lens needs some experiment. Most lenses have their sweet spot around f8-f11. Any higher aperture number causes diffraction which reduces image sharpness. Too low aperture number leads to soft photos especially on cheaper zoom lenses.

After all this setup the last step is to aim the center of the moon and select the right exposure. There are calculators for moon photography but couple test shots give you a good idea anyways. Depending on your camera its exposure metering it might give totally misleading results so feel free to ignore it.

Take plenty of shots with different aperture and exposure times. At the post processing I use only green color component because it seems to have less noise compared to red. I also reduce saturation so the end result is black and white. Apply some sharpening, crop tight and upload to your favorite image gallery for feedback.

Canon EOS utility and tethered shooting preview quality

Canon DSLRs come with a software bundle and one of the applications is EOS Utility. Among other features it allows you to transfer your shots right away to your computer over USB cable and it also displays a quick preview of the photo on the computer screen. This is pretty handy because it is much easier to see results on the big screen. Obviously the USB cable length limits your movements so I guess people will use this for studio shots mostly.

I was playing around with this feature and I noticed that the preview had rather bad quality. After trying out different settings it turned out that shooting in RAW+JPEG mode instead of RAW only resulted better previews. Apparently the quick preview's RAW conversion outputs only low resolution images.