Tag Archives: Focus

Focus Stacking Issues

There was a meeting of the IPMS northwest branch at the Museum of Flight recently.  My friend Jim had given me a heads up about it taking place and, with a day free, I figured I would pop along.  The display as a whole gets its own post but this one was about my experimenting with focus stacking.  I went to this a previous year and took some focus stacking shots handheld to see how it would go.  This time I went prepared and took a bunch of shots.

I took a tripod and my macro f/2.8 lens to try and get detailed shots while isolating the background.  There were lots of models on display, some of which were really good.  However, they didn’t all make good subjects since many were displayed in amongst lots of other models.  I picked the ones I liked as a wandered around and them went back to shoot them.  Many of the stacks worked out just fine and I include an example or two of what worked well.  However, some of them just confused the software.

I use Photoshop to do my focus stacks.  However, on one of the shots that I really wanted to work well – the FW190 which had a diorama – things didn’t work well.  I decided to Google other software solutions and came up with two other applications for focus stacking.  I downloaded trials of both but neither managed to do a good job of it.  I guess this combination of shots just made it too hard for the software to make it work.  I can see the rear fuselage markings of the FW190 showing through the wing of the aircraft.  Maybe this is a function of the narrow depth of field of the f/2.8 shots.  The wing gets blurred out a lot when the rear fuselage is in focus and it decides to take that area as the one to give preference too.

All of this is to say, I have found a new aspect of this technique that needs further investigation.  My earlier experiments with focus stacking probably made it easier on the software.  I have now started to make it a bit harder.  Maybe I need to control the aperture to get things to behave the way I want.  That might have to be tailored to make sure I don’t get the background coming in to focus too much since that separation is something that I want to preserve.  If you have experience with this, I would welcome advice.

Focus Stack Animation

In some previous posts I showed the results of experimenting with focus stacking.  In those posts, I would combine one of the individual shots with the finished effort to show how shallow the depth of field could be on individual shots and how deep the focus was on the final image.  I was pondering whether this was an effective way of communicating the concept to someone when it occurred to me that animation might be a better way.  I created a new stack of images for a different subject but this time I used Photoshop to animate the movement of the point of focus through the shot and then show the final image.  This can then be an animated GIF.  I wonder, does this provide a better demonstration?

A Further Trial in Focus Stacking

In a previous post I wrote about a focus stacking effort I made with images of a model aircraft at a show.  I had been meaning to have another go at this and do so in a more controlled environment.  I then ended up buying myself a macro lens for use in my negative scanning efforts and immediately started playing with it to shoot things close up – it’s a macro lens for goodness sake!

As an f/2.8 lens, when shooting macro shots, the depth of field is really shallow.  This got me thinking about trying another focus stack.  A small Leatherman seemed as good a target as anything.  I set up with manual focus, put the camera on a tripod, went to manual exposure and then shot a sequence with small changes to the position of focus for each shot.  Then it was off to Photoshop.

Photoshop did a pretty good job really.  The distortion of the areas out of focus means that the area that the subject covers can vary quite dramatically as the focus shifts backwards and forwards.  The algorithm did well getting things masked and blended.  The only bit it struggled with was at the very top where the knurled edge seemed to confuse it a bit.  The top shot is the finished effort while two others are included to show how much things are out of focus in the individual shots.

My First Attempt at Focus Stacking

I first read about focus stacking a long time ago and I have been meaning to try it for ages.  The premise is to take a series of shots with the focus set in different positions throughout the scene and then to use software to blend the images together to create on image with focus all the way through the shot.  This seemed like a simple thing to have a try with but I never got around to having a go.  Then I came across a situation that looked like it might be a good example to try.

I was visiting a model show at the Museum of Flight.  I was taking a few photos of some of the more expertly crafted models on display.  I was shooting with a longer lens and using a relatively small aperture to try and minimize the shallow depth of field that you get when shooting small objects close up.  I decided to shoot a model of a Fairey Gannet and the shallow depth of field triggered something in the deep recesses of my brain about focus stacking.  Of course, I had not planned for this so no tripod and just an effort to get focus on different parts of the model without moving the camera too much.

I took the shots and got on with my visit.  When I got home, I almost forgot about the stacking experiment but, fortunately, I did remember.  I exported the images to Photoshop as layers of the same shot.  Then, since they were hand held, I did an Auto-Align action to get them in place.  After that, Auto-Blend was selected.  It seemed to realize that they were a blend stack rather than a panorama – quite clever – and the software quickly did its thing.  Despite not taking too many shots and do it all hand held, the result came out pretty well.  The top shot is the finished product while the lower two show the extremes of the focus range for the original shots.  If I had managed a shot focused right on the back of the fin, the result may have been a bit better still.