Hi all! Recently started playing with macro a bit more using my old Canon 50D and a wemacro rail. One of my hobbies are carnivorous plants which is my current subject to take pics off at the moment. When taking stacks of sundew plants, you have the lovely dew drops. Around these complex shapes there's a blur most of the time which I can't seem to get rid of whatever setting I pick. Any suggestions?
I've spent a lot of time on this issue. But even so, I welcome others who are more knowledgeable about optics to correct or improve my answer.
The normal set up of a camera has the sensor fixed in place, and the lens moves when you refocus.
Distance to the image (Di) divided by distance to the object (Do) = Magnification
When you move the lens closer to the sensor to focus on the the farther object, Di decreases and Do increases. The magnification gets smaller.Apparently, HeliconFocus deals with this by changing images sizes to match the magnification. That's good, but it leaves a big out of focus foreground object next to the in-focus background in the faraway images. You end up with halos around near objects since you your faraway images have a big "shadow" of the nearby object blocking the in-focus far away object, and the nearby images have no in-focus pixels of the faraway objects.
I spend a lot of time and cloning background data onto the halos if they are annoying. I use some combination of the stamping tool and the spot healing tools in Photoshop.
See the images I am posting later today of the orchids for an example. Look at high contrast original and final, and compare the halos around the nearby leaves. It's not perfect, but it's a useful improvement.
This is my first post. I agree completely with Phil on the Halos. It is quite frustrating. I was hoping to hear that Phil's Phase One would have solved the problem. What lens are you using, Phil? How are you advancing the setup? Is it the NovoFlex? I am working a number of different algorithms with no success yet. It has to be an Adaptive Interpolation. The only group that I have heard may be able to help after we use our Helicon is "Smart Edge", but I can't find out who owns it. It's not on the market yet. I know it is not Adobe.
I only photograph flora/grass. Mother Nature's middle name is Chaos. I have learned to smile, and I realize she will win most of the time, because I stack at least 200+ images into her final beauty. I adore the challenge.
Hello once again Remco and Phil,
The concept of the halos is full of trade-offs. Could it be Blurring or maybe Alliasing? This seem to be similar to the complex nature of enlarging a photograph. Algorithms don't treat all pixels equally.
I decided to step away from the math for some experiments.
Light! I now only use macro flashes (2-4). Each can be calibrated to whatever the individual flower or grass tells me it needs. I then have found that the lower the better. Raising in Post. This improved the edge halo about 25%, if it is edge halo.
That led to 2 sleepless nights. Passive white reflection (small, 12"). The more the better. I need each of the 12" reflectors to have 100 tiny reflectors. You can probably understand where I'm going with this. I happens more with grasses or when there is a lighter object on top of a darker object. No body makes this type of reflector. I don't have time or the inclination to invent one at my age. It has solved another 25% of the problem.
I'm still not sleeping. So, decided to go crazy and really pump up the stacks. It has definitely helped.
I am still experimenting with all of these and other variables. Six more methods planned.
If you have a lot of complex structures in the foreground and background you may want to use Method C (pyramid) instead of Method A or B.
Method A and B are great for flat surfaces without too many changes in dimensionality or rather geometrical figures. With complex overlapping, dimensional stuff Method C often gets better results, though the contrast sometimes suffers.
Personally I would suggest combining methods for the cleanest results and/or render the foreground and background objects separately and then combine them.You could even combine these rendered images again in Helicon Focus without resorting to Photoshop.
EDIT: as for the original image I would probably change your shooting parameters as well.
With a 100mm macro lens f 2.8 at 100um steps isn't quite necessary or beneficial unless you're shooting at 3x or 4x magnification and you're diffraction limited. At f2.8 you will have a very shallow DOF and that will cause a very sharp separation of foreground/background elements - which will make if more difficult to then stack them properly.
Instead you might want to try f4.0 or maybe even f5.6 - as a benefit you will need fewer images and your step size doesn't have to be quite as small.