The Perfect Camera for Model Railroad Photography?

 

I recently acquired a Canon R7 mirrorless digital camera with the kit 18-150mm lens. I purchased this camera as my former Canon 70D was over 10 years old. While it was in excellent condition, the newer cameras have surpassed it in technology. When I read about the Canon R7 I realized it had some great features for model railroad photography, particularly the automated focus bracketing feature and  high resolution. I also was impressed by its lack of focus breathing at wide angle focal lengths.  

Last weekend I put the camera to a thorough test at a photo shoot for a magazine. I shot over 30 different scenes and about 10 minutes of video. The camera exceeded my expectations. Alas, I cannot share those images here. But I did do a quick test using a photo from my railroad.  The image above is a test shot similar to the images I discussed earlier.

Resolution

This next image is a comparison of similar images from the Canon R7, a Canon 70D and a iPhone 13 Pro. The relative sizes of the images shows their native resolution. The blogspot software shrinks images to save space on their servers, so you can't see the images at their true native resolution without using a file sharing service to save the full images.  So I combined them in a single image to show the relative sizes.

The R7 is a 31 megapixel camera with 6690 by 4680 pixels. That means it can support a 22.3 inch print at 300 pixels per inch. That is more than enough to get a great two page spread in a magazine. 

The R7 uses a APS (i.e. crop sensor). You might think that a 31 megapixel crop sensor would have problems with noise at high ISO. But that isn't usually an issue with model railroad still photography as we use a lot of light and can shoot at very low ISO. I used ISO of 100 in this test image. For action photography, the higher ISO needed to help stop motion can lead to noise. But both the Photoshop camera RAW and the Canon Digital Photo Pro software that comes with the R7 camera are pretty good at removing the noise. 

I have found that cameras with APS crop sensors work better for model railroads than full frame sensors. I have had both. The crop sensor means the lens used on an APS camera have a telephoto effect. That forces you either move the camera back from the scene or use a wider focal length to get compositions that are the same as you would get in a full frame sensor. The bottom line is that you get more depth of field with a APS sensor in model railroad shots both for still and video shots. That is very helpful. Note this is opposite of what most other photographers want such as in portrait and bird photography, where they want shallow depth of field for the nice bokeh effect.  I discussed that topic in more detail in an earlier post here .

Close Focus Distance

Beyond the amazing resolution, the camera with the kit lens has an astounding close focus distance. The grass in the foreground was nearly touching the camera lens.  This obviates the need for a separate macro lens. 

The camera is more compact than the 70D so you can get it in some tight places. But the iPhones cameras are better for shots like that. 

Focus Stacking aka Focus Bracketing

The R7 offers automated focus stacking in camera. You enable this mode using a menu on the back screen. Once you enable focus bracketing, you then set the number of shots and  focus increment you want to use. The focus increment is not defined precisely, so you might need to experiment. I have been using 10-14 shots and a narrow focus increment for my model railroad shots.  There are some other settings for focus bracketing including a really neat one called "depth composite," which I explain below. You can find more info on this web page 

Next compose your image. Then select a point in the foreground where you wish the focus to start. Once you hit the shutter, the camera will automatically take a shot, adjust the focus point, and shoot again until it reaches the number of shots you specified or the focus reaches infinity.  The camera stores all the images on the card.

Example of stacked image using
in-camera Depth Composite. Note the problem
area in shingles as indicated by the circles.

If you selected to enable the Depth Composite setting on the camera menu, the camera will automatically make one stacked image from all the shots. That is amazing, but, I find it didn't give as good results as when I used Photoshop to blend stack.   Look at the roof in the image at the left. The in-camera depth composite did not do a good job of blending the roof shingles. 

Also, the camera saves the stacked image as a jpg file on the memory card. I prefer to shoot in RAW format not jpg.   So in my work flow to date I have not been using the focus bracketing with depth composite enabled.  

Instead I bring the stack of images into Photoshop. I use camera RAW to adjust the images. I synch all the adjustments, so the RAW images get the same adjustments. Then I do the align and stack in Photoshop. When photoshop is finished stacking, I flatten the image and do any special effects like sky replacement or adding smoke.

Focus Breathing

The kit lens also does not exhibit much focus breathing when doing the focus bracketing. Focus breathing (or lens breathing) is the phenomenon when the angle of view changes in your lens when you adjust the focus. When you focus from up close to infinity, you’ll see that the lens zooms out. It’s a small change, but a change nonetheless. 

The change also happens when you adjust in the opposite direction.  The lens will zoom in when you turn the focus ring from infinity to minimum focusing distance. If you go back and forth, it will zoom in and out. It’s as if the lens is breathing in and out, which is why it’s called focus breathing.

I could not detect any lens breathing artifacts when using this lens at a wide angle focal length. The artifacts would appear as out-of-focus fringes around objects that are closer to the camera. It is apparent in the iPhone image I posted above. Those fringes are very hard to correct  as you must manually replace the fuzzy areas using editing software  

Video 

I put together a brief video showing how the automated focus bracketing works. It really is quite simple. It only takes a few experiments to get it dialed in to how you want it. I used 10 images to make my stack. 

Bottom Line

The Canon R7 is an ideal camera for model railroad photography. It also rocks with a big telephoto for wildlife photography as it has very advanced autofocus capability, but that is a topic for a different blog