Subject moves with focus adjustment.

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Subject moves with focus adjustment.

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Started 2 years ago by spraynpray
Latest reply from jonnyapple
Related Topics:
1. SB400 Issues
2. AF Focus Adjustment; the wrong way to go?

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spraynpray

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I am intrigued by the possibilities of focus stacking but during the creation of my first stack, I noticed the image getting bigger as I focussed through it. OK, I don't have a nice Nikkor Micro lens, I was just using my kit 18-105mm at 100mm with +3 diopter close-up lens when I noticed it. I changed it for my 50mm f1.4 but that was the same.

Is this definitely something that goes away with a dedicated (read expensive) macro lens or is it a fact of life? If it doesn't go away, how the heck do you create focus stacks without hideous blur?

If any of you guys are into focus stacking, I would appreciate some pointers.

Thx,

Andrew.

Posted 2 years ago #
jonnyapple

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I'm not an expert, spraynpray, but I've watched what people have said here and one way around it is to use a macro rail. What you're describing happens with dedicated macro lenses, too.

Posted 2 years ago #
spraynpray

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Ah, sweet. That makes sense Jonny thanks.

More gear to buy then ;-)

Posted 2 years ago #
Plane

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I had done once on a microscope. But still not experienced.

I guess you may try to record in movie mode and focus stack all the frames.
But as for the Focus Breathing issue, I had never encounter on a dedicated microscope lens.

But I guess it will be worth a try.

Posted 2 years ago #
Drab

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Plane said:
I guess you may try to record in movie mode and focus stack all the frames.

2MP frames which are heavily and interdependently compressed with a perceptual encoder which relies on motion to hide encoding noise. ;)

Plane said:
But as for the Focus Breathing issue, I had never encounter on a dedicated microscope lens.

A - most microscope lenses are not internal focusing design, and
B - (As I Understand It) visibility of focus breathing is all about the ratio of near to far focal distance. With a microscope (or microscope lens mounted to a SLR) one is typically shifting focus by micrometers while in 1:1 macro work one is typically shifting focus by at least two orders of magnitude more while the focal plane is not even one order of magnitude different in distance from the lens nodal point. Therefore any focus breathing will result in magnification changes easily 100's of times less and most of us aren't good enough to see such.

Posted 2 years ago #
spraynpray

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OK guys, focussing rail ordered, can't wait to get started.

Oh boy, some of these stacking programs are unbelievably geeky :-| I just want easy to use with good results!

Thanks for the nudge jonny.

Posted 2 years ago #
jonnyapple

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I sure hope it works and I haven't led you astray, Andrew. As I said, I haven't actually used a macro rail!

Even if it doesn't, though, I've wanted one for a while because you can also use it to reduce parallax for panoramas by moving the camera until the axis of rotation goes through the nodal point of the lens. I think you asked about that months ago.

Posted 2 years ago #
spraynpray

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I have a decent grip on the panoramic technique now, but you are right, I could incorporate the macro rail into my home-made head to ease fine tuning.

I have to say that I still have reservations about this because what are you doing when you move the focus point through an item you are photographing? Moving closer or further away right? So why doesn't the image still get smaller or larger? I was surprised that even a prime lens changes the image size with focus and as you say that macro lenses are the same too, I guess I'll just have to play around with a rail to see what I can do.

I use Elements and Lightroom for PP - is there any kind of image alignment program that you know of jonny?

Posted 2 years ago #
studio460

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FWIW: "Breathing," or having image size change with focus distance, is common to most lenses (even, very expensive still and video lenses). Uber-expensive lenses designed specifically for cinematography (not HD video), are expressly designed to minimize breathing. I know that people have been putting Nikon F-mount lenses on PL-mount movie cameras for years (a number of adapters are available), but I'm not sure how you put a PL-mount cine lens onto a Nikon body.

Posted 2 years ago #
heartyfisher

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I have played with focus stacking and yes on my macro lens the image changes FOV as I change focus. However, the software compensate for this. and you should be fine. LOL! No need for that rail !! hehe!

Posted 2 years ago #
Pierre

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I have done a few stacks and usually in CS5, the alignment will increase or decrease the image size to fit recognizable patterns. That doesn't always work with subjects that do not have a lot of sharp edges or patterns such as in this one:

I basically had to do a lot of manual adjustment and ended-up aligning layers by hand and using masks to hole through the top layer. For the alignment, I made the top layer visibility down so I can see it superimposed on the layer below.

On subjects with more defined edges, there is usually no manual steps required.
In this stack, I had to do only a few manual adjustments as CS5 sometime makes mistakes in deciding what is in focus.
.
I bought a Manfrotto focus rail but have not used it yet.
Focus breathing gets even worst whith the distance between subjects such as trying to bring in-focus a near tree against a far backround.

Today, I will put a focus-stack on the PHOTO-A-DAY thread that required no manual adjustment, it was a 30 seconds job stacking 9 photos.

Posted 2 years ago #
jonnyapple

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I like how I keep saying I know nothing about this and you keep asking me questions, spraynpray. ;-)

I've tried CS4 and wasn't thrilled with the results (probably a problem with my technique in taking the pictures).
Here's a free solution (I'm going to try this today):
http://www.hadleyweb.pwp.blueyonder.co.uk/CZP/News.htm (installer for XP/Vista available if you click on the "installation" link)
Here's another that seems to be more user-friendly but less free (it does handle 16-bit files and raw files, though; I'm not sure what combinezp can handle):
http://www.heliconsoft.com/

Posted 2 years ago #
spraynpray

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"I like how I keep saying I know nothing about this and you keep asking me questions, spraynpray. ;-)"

Wassup jonny - you're a teacher aren't you? ;-)

I am installing CZP and have just joined the forum over there. It seems that program does re-alignment while stacking.

I'll get the shipper to redirect the rail to you jonny - it is cash on delivery.....

Pierre, those are nice images indeed.

Thanks guys.

Posted 2 years ago #
jonnyapple

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spraynpray said:
I'll get the shipper to redirect the rail to you jonny - it is cash on delivery.....

Then I'll have to tell my wife that my hands are completely tied and we'll just have to pay for it. Say, are you interested in ordering a 24-120 f/4 anytime soon? ;-)

Posted 2 years ago #

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Subject moves with focus adjustment.

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