Pls recommend some focussing rail for use with helicon focus

Shooting in macro mode, techniques, tips & tricks

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Pls recommend some focussing rail for use with helicon focus

Unread postby Guest » 09.11.2005 10:10

Hi, I have downloaded a trial version and using it with my Manfrotto 454 micro positioning plate.

The problem is that this manfrotto 454 is not smooth and the image I shot cannot be combined with the helicon focus (becuase the postioning of the subject change each time I move the cam-subject dist.)

So I am requesting recommendation for a focussing rail whichwill not have this problem. Of course - not the very expensive one.

Thanks

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Dan Kozub
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Joined: 24.03.2004 18:14

Unread postby Dan Kozub » 10.11.2005 09:54

I have no experience with the rails but i home someone will give you recommendation.

Please make sure you really need it. The most important is that your rail enables you to change the distance in small steps. If the object is shifted to the right/left or top/bottom, it is not really a problem - the program can align images (check autoadjustment parameters of the program).

If you still have doubts, feel free to send me a problem series of photos, I will check it myself.

Our ftp server: ftp://web10f6:123456@helicon.com.ua

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Saturdaze
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Joined: 21.03.2006 01:24
Location: California

Novoflex Castel-L

Unread postby Saturdaze » 21.03.2006 03:52

I am new to this group and the software, but the focusing rack I would recommend (and with no comparison with which to judge) is the Novoflex model Castel-L. Extremely smooth and with a fine scale for precise advance. Very simple design with several options for mounting to a tripod or a block.

http://www.novoflex.de/english/html/products.htm

Tim Ernst

Change focus or distance?

Unread postby Tim Ernst » 25.03.2007 17:44

This brings up a good question - is it better to change your FOCUS via the lens or change your DISTANCE via a rail? Or does it make any difference at all?

Tim Ernst in Arkansas

FredT
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Joined: 22.05.2007 05:27

Unread postby FredT » 22.05.2007 06:31

Does anybody have an answer to Tim's question. I'm also very interested in knowing the answer.

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Dan Kozub
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Unread postby Dan Kozub » 24.05.2007 08:33

Tim,

Focus/Distance dilemma:

I would say that rails give you more control because you know how you focus place is moving.

This is good method if you shoot from 10 cm and you move the camera for only 1cm. In this case the object does not change much from the first to the last shot.

But if the DOF is too big, you will notice dramatic change in object position and view angle. That will for sure cause artifacts in the final image.

For this cases I would recommend to change FOCUS, not DISTANCE. You camera stays on the same place, view angle is fairly the same, only focusing plane is moving through the scene.

This should create less differences between extreme shots.

I would be interested to hear if my reasonings are proven by your practice :)

richard1karash
Posts: 13
Joined: 25.04.2007 22:01

Focusing Rail, Re-focusing (lens or front std), Rear Std.

Unread postby richard1karash » 04.06.2007 01:36

I have been thinking about the question of moving the camera vs. adjusting focus.

It seems to me that the issue is to avoid changing the perspective relationship of elements of the image.

I think the perspective is most likely to change if you move the camera to focus on different parts of the scene. If the movement changes the perspective relationship of objects in the image, then you'll get artifacts. It's not a problem if your working distance is 150mm and you are moving 2-3mm. But, if the working distance is 150mm and you are moving 75mm, then perspectives may change.

I have a sample image to illustrate this. See below. (Dan, I'm happy to upload the stack.) The scene is ten golf tees in a bowling pin pattern with a playing card 35mm behind. The depth of the scene is 75mm from the closest golf tee to the playing card. The lens-subject distance is about 150mm.

More: Changing the focus shifts the lens forward and back, changing the perspective. Not as much as moving the camera, but some. In my test scene, I get artifacts changing the focus. It seems to me that to keep the same perspective, you want to avoid moving the lens. You can get different focal planes by using a bellows and moving only the rear standard (the "film") and not the front standard (the lens). It seems to me that this should come closest to maintaining the perspective in the scene.

Any comments?

-=- Rick
Attachments
MoveCamera.jpg
Moving the camera. Scene depth is 75mm. Lens-Subject distance about 150mm.
MoveCamera.jpg (131.66 KiB) Viewed 16346 times

richard1karash
Posts: 13
Joined: 25.04.2007 22:01

Focusing Rail, Re-focusing (lens or front std), Rear Std.

Unread postby richard1karash » 04.06.2007 01:45

Here is a photo of the setup that produced the image above.
Attachments
PerspectiveSetup-3390sm.jpg
Setup for the perspective test scene (previous post).
PerspectiveSetup-3390sm.jpg (102.45 KiB) Viewed 16345 times

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Dan Kozub
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Unread postby Dan Kozub » 04.06.2007 20:59

Rick,

Thanks for the samples.

You can create web animation from Helicon Focus (win version) and upload it to our ftp server (ftp://upload:nopassword@helicon.com.ua/httpdocs/) and then post the link to this forum.

Looks like this is difficult case as even changing the focus moves the lens and changes perspective.

Ok, one more crazy idea: set the camera on the small table, then change the focus so that the lens does not move (camera moves backwards). Maybe backward movement will compensate perspective change.

And one more major problem: When placing the lens so close to the object, you can actually see details _behind_ the object. I think that making smaller aperture should minimize this effect.

richard1karash
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Joined: 25.04.2007 22:01

Change in Perspective

Unread postby richard1karash » 04.06.2007 22:01

I uploaded the stack to the ftp server in a subdirectory JackOfSpades -- I'm on Mac so can't make the flip-movie.

Thinking more about this test image... I think the problem is that the camera movement changes the perspective BETWEEN ADJACENT SLICES, in this case, the last golf tees and the background card. That creates the ghosting and details breaking through the foreground objects. This test image is VERY difficult to composite.

It's a tough problem. Even if there is NO change in perspective, the camera can see around the foreground objects and the same pixels will be sharp in both the foreground and background slices. Only manual masking will get the right pixels into the final image.

Dan, your idea of holding the lens steady and letting the camera move is exactly what I had in mind... It's the same as focusing with the rear standard on a bellows, leaving the lens-subject distance unchanged. I think this will produce a better result.

Back to the practical... I set up the Jack of Spades test because I was worried about shooting a bouquet of flowers. I was worried the perspective shift would mess up the bouquet image. In practice, it's probably not a problem. I did another test showing that as long as the objects are distributed throughout the scene depth, it's not a problem, even when I make slices by shifting the camera.

The perspective shift problem does arise if I try to do the whole bouquet and THEN add another slice for the background. My conclusion: If the perspective changes from one slice to the next, then you'll get artifacts. If there's a big focus change between any two slices, it's very tricky.

Thanks again for Helicon Focus. The human eye takes in the whole scene and integrates over the focal planes unconsciously. With Helicon, I can make an image that matches better what the eye sees.

-=- Rick

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Dan Kozub
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Unread postby Dan Kozub » 05.06.2007 20:11

Yep, I've played with the stack a bit. It cannot be make perfect even with manual retouching. Some information is simply missing.

Here is web animation:
http://upload.helicon.com.ua/JackOfSpad ... mation.htm

richard1karash
Posts: 13
Joined: 25.04.2007 22:01

Thanks, Dan

Unread postby richard1karash » 19.06.2007 04:31

Sorry to be slow in replying.

Thanks for the animation. Yes, I agree that some info is simply missing, and this can happen in some situations. This was an artificial setup... I'm worried that I made it more difficult than a real life situation.

The real life I'm thinking about is a flower with stamen/pistil well in front of the petals. I've just done one of these and the "missing info" is not a problem in this real-life test. I'll post in another thread.

More on the question of this thread: Move the camera, adjust the focus, or (with a bellows) keep the lens in the same position and move the "film."

In shooting a flower, at 1:5 or so, it's academic: The lens-subject will be several times the lens-film distance. Because of this, the change in perspective is less a problem and the only ways to change to focal plane is to move the whole rig or refocus. Moving the rear standard is too sensitive; I couldn't get even six slices in my flower image this way. Moving the whole rig or changing the focus, I could get all the slices I wanted. In my 1:5 flower image, the perspective changes were just not a problem.

I think the situation reverses at higher magnifications... Above 1:1, I think it willl be easier to use a bellows, moving the rear standard to make the different slices.

Hope this is helpful to someone.

-=- Rick

JohnFR

Re: Change focus or distance?

Unread postby JohnFR » 03.08.2007 05:32

Tim Ernst wrote:This brings up a good question - is it better to change your FOCUS via the lens or change your DISTANCE via a rail? Or does it make any difference at all?

Tim Ernst in Arkansas


I bought (and returned) a Manfrotto focus rail because for what I was taking in macro (fungi) there was far too much distortion of perspective as the CAMERA approached the SUBJECT (using 1.25mm steps). So I am very much in favor of actually focussing the camera/lens at each step, so that perspective remains exactly the same. The rail cost over $100, so you'd want to be sure that you really NEED it before spending that money.

Jess
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Joined: 14.08.2007 18:04
Location: WA Olympic Peninsula

Unread postby Jess » 23.08.2007 03:40

About focussing rails: I bought a Manfrotto 3419 focussing rail, and I've no regrets. I shoot a D70s with a micro Nikkor 105 mm lens for close up and closer. Problems related to lens focussing, either back-to-front or the other way, have disappeared. I just set the lens on max close-up, and move the camera with the 3419.
I still have "halo" issues of a certain kind, but most of these can be corrected using Photoshop CS-2.
I've seen none of the "bowling pin" confusions so far, but I'm not ready to say that they've gone away.
Here (attached) is the result of 69 exposures of a hornet (killed by freezing). There were plenty of opportunities for "bowling pins," but none presented themselves. to my surprise. Thanks to Manfrotto and to Helicon.
Questions?
~jess
PS: Note the peculiar "halo" effect at wingtips. A mystery to me.
PPS: The genus is Dolichovespula, of course; not Dolichocephala. My apologies.
Attachments
For_Helicon_hornet.jpg
For_Helicon_hornet.jpg (57.03 KiB) Viewed 15241 times

Bob J

Focussing rail, and infinite depth of field

Unread postby Bob J » 11.10.2007 07:00

First, with respect to the focussing rail issue, I recently purchased two of the Novoflex Castle Q focusing rails, despite the fact that I already had one of the Really Right Stuff rails, and had ordered another. I was impressed by the overall smoothness of the device.

Unfortunately, I wanted to use this with the Canon MP-E 65mm macro lens, which for 5X magnification has a depth of field of about 0.095mm at f/8, and 0.048mm at f/2.8. The Novoflex advances approximately 7mm per rotation, so it would be necessary to guess at 1/70th of a rotation. That's essentially impossible, without a very high quality vernier adjustment.

The Really Right Stuff (and apparently the Manfrotto) advances by 1.25 mm per rotation, or 0.1mm per "hour" on a clock face, and that I can manage, especially with large dial as someone else suggested. The only issue is that there is a significant amount of backlash, so you have to advance the screw in only a single direction. You may also have to tighten the locking screw just enough to prevent wobble, without preventing adjustments.

I wish that there were long-length screw-thread rails that had vernier dials or controls, and maybe such are available for microscopes, but I haven't found any.

The Really Right Stuff rails may not be as available as the Manfrotto, because they don't use or support a dealer network, but you can find them on the net, and they are quite reliable.

Having said all that, my first attempt last weekend ended up with a truly ugly image. I was trying to take a picture of a rosemary flower about centimeter in size, at 3.3X. Despite using a very sturdy tripod and two Wimberley plamps to hold the branch, the wind blew the individual petals too much. The result was a number of sharp in-focus images that were displaced horizontally, with disasterous results. Maybe if I had been able to edit individual frames in Photoshop, this could have been avoided. As it was, I wasted several hours taking the pictures and post-processing them, only to keep the first picture with sharp pistols or stamens (I can't remember the difference) and pleasantly blurred petals.

Second issue:

I would like to take some pictures that really highlight the essentially infinite depth of field that Helicon Focus will permit. For example, a field of flowers that stretches out to the distant mountains.

Now, my Canon 90mm T/S tilt and shift lens (or my long gone but sorely missed Sinar P view camera) would handle that chore easily, with a simple tilt adjustment, although it might not focus as close as I would like without an extension tube.

However, suppose I'd like to show a dandelion or flower in the foreground that fills the frame vertically, and at the same time show the infinite depth of field with a mountain or cityscape in the distance, behind the flower.

George Lepp, the nature photographer who first introduced me to Helicon Focus at a seminar, showed an image of an arch of an ancient bristlecone pine tree, with the mountains framed in the center of the "hole" in the tree. There is no way that a Scheimpflug tilt will cope with that. However, he had nothing but sky between the tree and the distant mountain that needed to be in focus, so careful Photoshop work would have been sufficient.

But what if the intervening details were also important -- what then?

So the question is this. Suppose I use the Canon 180mm macro and focus on the flower in the foreground, at close to 1:1 or whatever it takes -- maybe 1:2 or 1:5.

What strategy should be followed to get the distant mountain in focus and anything in between as well?

If I change the focal point of the lens, is the perspective going to change so much that the various frames won't match up? I clearly can't change the focal distance enough to make a difference, so changing the focal point of the lens is going to be a necessity sooner or later.

Should I consider making up one composite image of the relatively near field subjects, and then using panorama techniques to blend more conventional images of the intermediate and long range viewpoints?

For short differences in working distance, the normal recommendation would be to change the focus distance via a rail, while leaving the lens's focal distance alone, but clearly that won't work for an object at infinity.

Has anyone experimented with using a combination of Helicon Focus and panoramic photography to extend the coverage in multiple dimensions, X, Y, and Z?

Any help would be appreciated. I'm sure that I can figure this out eventually, but it might take multiple weekends of experimentation plus post-processing, with attendent frustration along the way.

Bob J.


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