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Author Topic: Canon and macro photography  (Read 6011 times)
Alan Matuka
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« on: April 10, 2012, 05:26:14 AM »
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I have a question about Canon tilt shift 90 mm lens...

Recently I did some jewelry shots using Canon 5D mk II and 100 mm macro lens, and although I did expect some problems with depth of focus it was worse than I expected  Sad
Five years ago I would have solved that problem easily - using Sinar 5 x 4 and applying some movements.

I guess 90 mm tilt shift is the answer - but I am not sure about it's focusing abilities. Since it's not the macro lens I guess I would have to use extension tubes...

Could you please give some advice... Maybe someone has a first hand experience :-)
Thank you
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Tony Jay
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« Reply #1 on: April 10, 2012, 05:53:40 AM »
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IMHO:

Using extension tubes would allow one get the magnification I assume you are looking for however the depth of focus (field?) would be minimized in the process.
Using tilting to overcome issues of focus may not work since altering the plane of focus with such a thin or shallow depth of field might well leave different areas of importance out of focus.

Have you considered focus stacking, either with PS5 (or 6 when available) or Helicon focus?
Helicon also sell a utility program that can control things like focus adjustment when a computer is tethered to the camera that is exceptionally useful when using a macro lens. One is able to precisely control what is in focus and what is left out of focus. Also, with cameras like the 5DII, live view can be projected to the computer screen (far bigger and much easier to see what is going on).

Food for thought.

Regards

Tony Jay
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BartvanderWolf
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« Reply #2 on: April 10, 2012, 06:03:36 AM »
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I have a question about Canon tilt shift 90 mm lens...

Recently I did some jewelry shots using Canon 5D mk II and 100 mm macro lens, and although I did expect some problems with depth of focus it was worse than I expected  Sad
Five years ago I would have solved that problem easily - using Sinar 5 x 4 and applying some movements.

I guess 90 mm tilt shift is the answer - but I am not sure about it's focusing abilities. Since it's not the macro lens I guess I would have to use extension tubes...

Could you please give some advice... Maybe someone has a first hand experience :-)

Hi Alan,

If a tilt of the focusplane would solve your DOF issue, I'd say that the 90mm with extension tube(s) is a viable option. The TS-E 90mm is not optimized for Macro use, although it will work. It has a rather symmetrical lens design, so it would not change its focus quality too much at shorter distances.

However, when the tilt alone doesn't solve the issue (i.e. the subject is not only tilted but also has a certain thickness), I'd recommend considering focus-stacking. That will allow to take benefit from the best lens you have for the job at hand, and yet be liberated from the physical DOF limitations inherent in Photomacrography.

Cheers,
Bart
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Alan Matuka
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« Reply #3 on: April 10, 2012, 06:54:50 AM »
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thank you for your help  Smiley

I did consider focus stacking, but there is a small problem  Roll Eyes
one should take several images and in each of them focus should be at the different point in the shot...
there are two ways to change the focus - on the lens and by minimal movement of the camera...
several people said second option is the right one, and it's done with use of macro-focusing rail - which i don't have...

in the other words - since it is impossible to move a tripod precisely just for 2 mm I'd have to refocus on the lens for each shot...

any experiences with that ?

thanks  Smiley
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Tony Jay
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« Reply #4 on: April 10, 2012, 07:12:02 AM »
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Hi again Alan

I did consider focus stacking, but there is a small problem  Roll Eyes
one should take several images and in each of them focus should be at the different point in the shot...
there are two ways to change the focus - on the lens and by minimal movement of the camera...

I think I already have an answer for this question: Helicon remote, the utility I mentioned before.
When a computer is tethered to the camera with Helicon remote installed with alittle bit of help from you the utility once you have shown it where you need to focus will automatically calculate the number of exposures required and the focus shifts required. The idea is to eliminate any gaps in the focus.
When you tell it go the utility will also control the camera during each exposure to ensure that each exposure is approriately focussed to cover the range required.

Regards

Tony Jay
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Tony Jay
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« Reply #5 on: April 10, 2012, 07:28:32 AM »
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Addendum:

I am bit tired writing this so apologies for the spelling and grammer errors in the last post.

I also neglected to mention (the most obvious thing of all) that obviously the camera needs to be mounted on a tripod.

BTW even using a focusing rail it is very difficult not to get gaps in the focusing because the focusing intervals are not evenly spread through the scene. Close to the camera they are closer together and progress to further apart away from the camera.
Helicon remote calculates all of this and makes sure there are no gaps during execution of the series of shots that it controls.

Regards

Tony Jay
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BartvanderWolf
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« Reply #6 on: April 10, 2012, 08:07:36 AM »
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thank you for your help  Smiley

I did consider focus stacking, but there is a small problem  Roll Eyes
one should take several images and in each of them focus should be at the different point in the shot...
there are two ways to change the focus - on the lens and by minimal movement of the camera...
several people said second option is the right one, and it's done with use of macro-focusing rail - which i don't have...[/Qu

in the other words - since it is impossible to move a tripod precisely just for 2 mm I'd have to refocus on the lens for each shot...

any experiences with that ?

Hi Alan,

Yes, I use both methods, depending on the specific scenario.

Ideally, one would keep the entrance pupil of the lens stationary, and only change the sensor position to focus at a different plane. That indeed requires a very special setup, a rail, a lens holder and a camera body holder with a bellows in between. The benefit is that perspective doesn't change between focus brackets because the entrance pupil remains stationary with respect to the subject. This is a very specialized type of focus stacking, and more common with extreme macro magnifications and dedicated reversed lenses.

The next best solution is either a focus rail with an accurate positioning capability, or refocusing the lens (either manually, or automatic with e.g. Helicon Remote). The (arguably) better of these two solutions is probably the one where the entrance pupil moves the least. However, it is very difficult to find out where the entrance pupil is when using internal focusing lens designs. Nevertheless there is a reasonable chance that refocusing the lens changes the perspective the least. Helicon Remote is a great help if you can shoot tethered.

If you (plan to) do this type of work a lot, then I can whole-heartedly recommend a device like the Stackshot by Cognysis. While a relatively steep investment, it will save you huge amounts of time. I just set it up and go do something else while the stackshot goes through the series of shots with extremely high mechanical accuracy. Especially with magnificatons larger than 1:1, where DOF is practically non-existent and an image may require 100 shots or more, it's an indispensable workhorse.

So, try refocusing first to see if focus-stacking suits your needs. You can always invest in a T/S lens (if you subjects are flat but only tilted) or other hardware later, if your requirements justify it.

Cheers,
Bart
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Alan Matuka
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« Reply #7 on: April 11, 2012, 04:25:38 AM »
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thank you both for your answers  Smiley

I am doing a pitch for a jewelry job, where I should shoot around 300 rings and other similar pieces in a relatively short time.
In order to speed up the process I will first try 90 mm tilt shift, and then focus stacking with Photoshop.

Also, as soon as I can I will try Helicon Remote.
I am really not sure how much work of that type I will have - but had a look at Stackshot and system looks good. Certainly is a good investment if one plans to do great deal of macro shots.

thank you again, I will let you know of the progress  Smiley

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Ellis Vener
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« Reply #8 on: April 11, 2012, 10:50:09 AM »
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My two cents from the nosebleed balcony:

The parameters of the project you describe -"300 rings and other similar pieces in a relatively short time" -makes me think your client has a minuscule budget.

Assuming the jewelry involves precious metals and gemstones which need to be very carefully lit to make them appear as valuable as your client wants his customers to think they are,  if indeed the budget is really small, I'd politely decline the job. 

Why? Good lighting takes time and fine-tuning the lighting for individual gemstones takes even more time and an assistant. Adding the entire focus stacking process to each piece takes time. Retouching - and there will be retouching needed - takes time. This doesn't include the time you'll need for the necessary breaks so you can keep your concentration up. So there fgoes the idea of "A relatively short time".

If you haven't done this kind of work before,  see if you can borrow a couple of pieces so you can work out how time, skill and what kind of tools each piece will need to be done right. That way you can work out for yourself whether it is worth it to do it for the proposed budget or  make an informed, backed by examples,  pitch for a larger budget and time frame.

Also a large project requires quite a bit of pre and post shoot organization as well.

My opinion is worth what you paid for it but it is informed by my experience. Of course it may be the case that for you  that what ever the budget size  is it is worth it for you  to spend a  lot of time to do it for the cash flow and experience.
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Ellis Vener
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Creating photographs for advertising, corporate and industrial clients since 1984.
Alan Matuka
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« Reply #9 on: April 11, 2012, 12:41:21 PM »
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@ Ellis

first, thank you for your advice  Smiley

You are right - client does have a minuscule budget. And that is why I would like to simplify the process.
Most of the time I shoot advertising still life, and am used to relatively complex lighting scenarios. Also, I have done several large museum jobs shooting crockery, porcelain and glass, and am aware that post production takes at least as much time as shooting.

So, your question - is it worth taking this job ? - is absolutely valid.
I have done some tests and know that it will take more time than planned. Still, most of the pieces will be gold or silver and as far as I know only some will have gems - diamonds.
I guess it is worth taking this job for experience and cash flow - because I do enjoy doing complicated still life shots.
Also, since the budget is small there is no way I would do image staking for every single shot - possibly for several shots that may be used for posters or book cover.

I see this job as an opportunity to learn something new and to add some new clients to my list.

of course, at the end of the job I will curse the day I took it  Roll Eyes

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snoleoprd
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« Reply #10 on: April 13, 2012, 09:00:05 AM »
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If you want to try focus stacking, Zerene Stacker produces less artifacts in my testing and is a whole lot cheaper than Helicon, it was written by a user of Helicon who was not happy with the stacking output. Also if you have an android tablet or phone there are apps that will do the focus stacking. I also use the Promote Controller, which has lots of other applications. Just some options to reduce the cost.

Since there are a lot of subjects you could set it up in an assembly line fashion, if you use the promote or android setups it would be a matter of doing the initial setup and then just swapping the item and pressing the keys to start the procedure. You could batch process the images and that could reduce time.

Just some alternatives.

Alan
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Alan Smallbone
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Alan Matuka
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« Reply #11 on: April 13, 2012, 11:23:20 AM »
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@ snoleoprd

thanks, I never heard of Zerene Stacker...
I guess it could be bought online... and hope that it works on mac  Smiley

I did some tests yesterday, and am not too happy with resolution on Canon 100 mm macro  Undecided
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Walter Schulz
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« Reply #12 on: April 13, 2012, 11:45:11 AM »
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I did some tests yesterday, and am not too happy with resolution on Canon 100 mm macro  Undecided

Either your lens is a lemon or you're doing something wrong.
Do you have an image file to share?

Ciao, Walter
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BartvanderWolf
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« Reply #13 on: April 13, 2012, 11:49:32 AM »
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I did some tests yesterday, and am not too happy with resolution on Canon 100 mm macro  Undecided

Hi Alan,

Which aperture did you use?  Anything narrower than f/7.1 on a sensor with 6.4 micron sensel pitch will start to lose contrast due to diffraction. You'll need to spend more effort on (deconvolution-) sharpening to mitigate that loss. That's where one of the benefits of focus stacking comes in, the lens can be used at its best aperture (e.g. f4 or f/5.6) although at the cost of requiring more focus steps to cover the DOF range.

Cheers,
Bart
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Alan Matuka
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« Reply #14 on: April 13, 2012, 12:05:06 PM »
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Hi Alan,

Which aperture did you use?  Anything narrower than f/7.1 on a sensor with 6.4 micron sensel pitch will start to lose contrast due to diffraction. You'll need to spend more effort on (deconvolution-) sharpening to mitigate that loss. That's where one of the benefits of focus stacking comes in, the lens can be used at its best aperture (e.g. f4 or f/5.6) although at the cost of requiring more focus steps to cover the DOF range.

Cheers,
Bart

I did several tests... at first I shot at f 8, but later went to f 16 od f 25...
also, it didn't help that I shot white gold on white bachground...

I will post some shots...
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Walter Schulz
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« Reply #15 on: April 13, 2012, 12:08:01 PM »
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An aperture number that big will cause severe resolution loss. Use f/4 to f/8 for best resolution.

Ciao, Walter
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Alan Matuka
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« Reply #16 on: April 13, 2012, 12:24:39 PM »
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first image was shot at f 16, second at f 20

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Walter Schulz
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« Reply #17 on: April 13, 2012, 12:38:25 PM »
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That is not working for 2 reasons:
- Diffraction causes severe resolution loss
- If you scale down an image you will not be able to tell anything about the original image concerning resolution. Local contrast will be lost and resharping has to be done and therefore we are looking at a very different image now.

Ciao, Walter
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Alan Matuka
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« Reply #18 on: April 13, 2012, 12:42:34 PM »
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here is a sample of a shot that I would be happy with... so, that is a target...

http://zlatarna-dodic.hr/index.php?link=proizvod&vrsta=srebro&id=114

considering number of shots on their site and the market I doubt they had a budget for elaborate postproduction ( i.e. I guess it's done as one shot )... of course, I might be wrong  Undecided

also, I am not sure that kind of resolution ( check the diamond ) could be achieved on 100 macro... it may have been shot on Hass...

there is one other thing... when shooting I used manuel focus and switched to ' 35 cm distance ' - opposed to ' 48 cm '...
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Alan Matuka
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« Reply #19 on: April 13, 2012, 12:46:46 PM »
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That is not working for 2 reasons:
- Diffraction causes severe resolution loss
- If you scale down an image you will not be able to tell anything about the original image concerning resolution. Local contrast will be lost and resharping has to be done and therefore we are looking at a very different image now.

Ciao, Walter

in the other words I should post original image, but it is too big for attachment  Undecided

what do you mean by ' Diffraction causes severe resolution loss '
diffraction in the object ?
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