Macro phtography and photo stacking.

[Batmeat]

I'm running into a problem with my macro lens, but maybe I'm using it wrong. Here is what I use:

Nikon AF-S Micro NIkkor 40mm 1:2.8

The problem in having is as follows:

I take a macro shot of a bug(or anything for that matter), but I can't manually focus on other parts of the insect without changing the photo depth. This makes photo stacking super difficult. The lens has a manual feature, but in order to bring other parts of the insect into focus, I have to zoom in on the bug. I'm fairly new to macro shots. Am I doing something wrong, or do I need a better lens? Camera is mounted to a tripod so it doesn't move.

partial focus
Image stacked

See how the first picture only has part of it in focus. I can't focus on any other bug part without zooming in or out, which makes photostacking dang hard as seen in the second picture.

 

[CuriousMike]

I think you're saying
1. Changing focus doesn't change the focal plane. Weird.

2. "Zoom in on the bug" - this means you have to physically move the camera closer/nearer to change the focal plane. That would move the focal plane. But so should adjusting the focus.

What is the near-focus for the lens? Maybe you are starting closer than the minimum focusing distance for the lens.

 

[FeuerFrei]

They make slide rails that mount on your tripod, and let your camera slide forward and backward for macro photography.

 

[Batmeat]

Let me try to be more clear now that I have more time.
I take a picture of the bug making sure the antennae are in focus. That makes everything behind the antennae( the head and body) blurry because the depth of field is so narrow/short. In order to bring the head in focus I have to physically move the camera closer to the bug. This then makes the antennae out of focus, but enlarges the head on the picture. Having to move closer to the bug in order to bring all the body parts in focus distorts the overall picture when I stack them.

Make a more sense?

 

[rahul]

What aperture are you shooting at? Your depth of field will increase as you stop down. Try shooting at around f/16.

 

[CuriousMike]

I know nothing about macro photography so maybe I'm misunderstanding how this works...

Why are you not manually focusing at the front, then a little deeper in, then a little deeper in... all while keeping the camera static?

 

[Batmeat]

I know nothing about macro photography so maybe I'm misunderstanding how this works...

Why are you not manually focusing at the front, then a little deeper in, then a little deeper in... all while keeping the camera static?

Because I can't. Rotating the lens to focus makes the subject bigger or smaller. This jacks the proportions of the subject all up

 

[corkyg]

Because I can't. Rotating the lens to focus makes the subject bigger or smaller. This jacks the proportions of the subject all up

That suggests you are trying to focus with the zoom control. Focusing does not normally change the image size..

 

[twinrider1]

• Decrease the aperture (bigger number) to increase depth of field so you don't have to focus stack.
• Try a longer lens.
• If you have to focus stack, move the camera instead of changing your focus.

Play with this and see how shallow your DOF is at f/6.3 and how it increases if you move to f/22. It's still small, but it might be enough so you don't have to stack. http://www.cambridgeincolour.com/tutorials/dof-calculator.htm

 

[turtile]

That suggests you are trying to focus with the zoom control. Focusing does not normally change the image size..

It does; many macro lens don't have internal focusing which moves the front element as you focus. And even ones that do have internal focusing will change the focal length as they focus closer.


Using a longer lens is really the only thing you can do to avoid the problem.

 

[EOM]

Focus breathing... it's a known phenomenon. Even stepping the aperture all the way up can only help so much. It has to do with the way the lens elements align themselves as you focus.

 

[Syborg1211]

Focus breathing... it's a known phenomenon. Even stepping the aperture all the way up can only help so much. It has to do with the way the lens elements align themselves as you focus.

That's crazy. You'd think with macro lenses that focus stacking was the intended use for that. I can't believe there would be that bad of focus breathing in a macro lens. I have an internally focusing 105mm macro and haven't seen any issues like this.

 

[EOM]

That's crazy. You'd think with macro lenses that focus stacking was the intended use for that. I can't believe there would be that bad of focus breathing in a macro lens. I have an internally focusing 105mm macro and haven't seen any issues like this.

I'm traveling right now but I'll be home Friday and can test a bit. I've got the 40mm f/2.8, a 85mm f/3.5 and a 105mm f/2.8 and see if it's that specific lens or if that focal length is just somehow more susceptible to the effect.

 

[Batmeat]

• Decrease the aperture (bigger number) to increase depth of field so you don't have to focus stack. Didn't do anything noticeable
• Try a longer lens. Trying to borrow one now
• If you have to focus stack, move the camera instead of changing your focus.
  

This is what I'm trying not to do as it distorts the subject(bug) size making photo stacking pretty hard.


Play with this and see how shallow your DOF is at f/6.3 and how it increases if you move to f/22. It's still small, but it might be enough so you don't have to stack. http://www.cambridgeincolour.com/tutorials/dof-calculator.htm

I like this calculator tool though. Pretty nice.

 

[twinrider1]

I don't think it will distort the final image.
Ok, so you have the front of the bug in focus and the distance is 6". As you move forward, the part of the bug that will be in focus remains at 6" and will have the same level of magnification. You're slicing through the bug, keeping the in focus portion of each pic, and discarding the rest. It's okay that the out of focus sections are changing in size. The software junks that part and keeps the in-focus portions and stitches them together.

 

[bigi]

I've used Helicon Focus and Control my Nikon. Both work well, but I do prefer Helicon due to its very easy focus stacking control.

It also allows for very good adjustment of focus increments with preset overlaying ranges.

Basically, you set up start and end points. Once done, the software calculates all the steps based on DoF for your body/lens combo.

Very convenient.

Once done, I use PS focus stacking for the images.

 

[bigi]

Just read some posts...

There is only so much one can achieve by using larger F stop. It does not help too much with macro shots. F8 with "normal" distance is very different than F8 with macro focused lens.

For 99.9% of macro work to get DoF of meaningful range focus stacking is must.