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 Replies: 16 / Views: 3,517 |
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Pillar of the Community
United States
4038 Posts |
I've always been careful to make my setups very stable to avoid external vibration. I use a stand similar to the Santoku I made for SuperDave, and have had no complaints about external vibration messing things up. The coin is sitting on a surface that is bolted to the mechanism the camera is mounted to, and they all move and vibrate together. Any small vibration is quickly damped. However, I've had complaints for a long time about a lingering fuzziness I see in my shots. The fuzziness has always gotten worse as I increase the magnification of my shots, so I figured it was due to some sort of vibration. On top of this I've seen many shots from Canon cameras that have a "so easy to look at" quality that my shots just don't have. As it turns out, many Canon's have a special shutter mode that is not documented but has the effect of letting the vibration caused by the shutter dampen-out before starting the exposure. I figured this may be the reason for my fuzzy images, but have not taken the plunge to spend another couple thousand dollars on a new Camera to test the theory. I got some suggestions from the Photomicrography Forum to try using a flash to "freeze frame" the vibration. Several folks there stated this is sometimes a silver bullet for vibration problems. Another guy suggested pulsing my LED light while the shutter was open. This seemed such an easy experiment I decided to try it. This was all predicated by a test I was doing on a new Nikon 3x objective I just received. The image looked absolutely stupendous in Live View, but the captured images were comparatively fuzzy. Seemed a great opportunity to test the new method. First image below is with my "normal" method using Live View with light close to the coin to achieve a 1/125sec exposure. Second image shows the same shot with the light pulled well away from the coin. This resulted in a 2-Sec calculated exposure. I set the shutter to 3-Sec in manual mode, and covered the light in a darkened room for the first 1-Sec, then uncovered for remaining time. Differences between the images are completely shocking to me. I had no idea the small amount of residual vibration from the shutter/camera were causing me so much loss of sharpness. This is the dawn of a new day for me and I will be trying the method on full-coin images next to see if I can get that "easy to look at" sharpness I have been so long searching for. Here's the original:  And here's the delayed / long exposure  |
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Moderator
United States
23522 Posts |
That's astounding.
Even more astounding, we apparently still don't know just how good your Printing-Nikkor actually is....that's scary.
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Pillar of the Community
United States
3076 Posts |
once I was a master in my own field, Even to view NEW IDEA or principle,AND results ,,,such a thing is amazing..
Once again you are leading the way RAY, and its not that they need to be your own idea's but rather that of all the ideas you receive and absorbe and trial and error, you humby post here...Even my Master had a master.... and new knowledge will pass to knew students...
RAY, Most of your shots are within the rigid stand, to eliminate any other issues , so my understanding is your thread is within the camera it self...? yes? My meaning is.....while to stabilize the best photo's, we use he tripod
or what ever..copy stand, Delayed shutter so we don't introduce our own vibrasions into the shot......
I'm simply saying this , as for the NEW basics
we still need to stabilize all of the above, and whats happening in side the camera...yes? as far as shutter Vibration......MY thoughts are.....RAY
you may be onto something new, its FAR above what you have shown us, in your understandings,
I
think....
All can agree Master ....you lead the way, in things we nevre thought of, and see with yopur posts...
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Moderator
United States
23522 Posts |
When you're doing something as exacting as macro photography, the mechanical action of the shutter itself is enough to introduce vibrations that affect the quality of the shot. Ray demonstrates this above, by having the shutter act before any light whatsoever is allowed to fall on the coin.
Thing is, Canon has had that problem already solved for years in some of their dSLR's, including every Rebel since the 450D. Canon uses an electronic first shutter - nothing mechanical happens whatsoever with the first shutter.
With dSLR's the shutter is not the aperture snapping open and closed. It's two "curtains." The first, top curtain is closed when you snap a shot, while the second, bottom one is open. When you hit the button, the first shutter slides open from left to right, allowing light through. The second then immediately follows, closing from left to right, and the actual opening through which light actually flows is more like a slit proceeding across the subject than an actual full opening except for long exposures.
It's that first shutter snapping open that causes the vibrations. The second shutter also causes vibrations, but only at the end of its' travel when the shot is complete anyways.
Since the Canon uses an electronic solution for the first shutter, the vibrations which Ray found a solution for do not happen. I would expect Ray's second, clearer shot to be the "usual" result from a Rebel-series dSLR.
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Pillar of the Community
 United States
4038 Posts |
Yep, this is the first time I have been able to prove the vibration from the shutter is causing the problem I thought I was seeing. What I saw was excellent sharpness in the Live View screen, but a much fuzzier captured image. Seems primarily to affect the higher magnification shots, where any small amount of movement can mess things up terribly. The shots I show above are at 3x. I have tried the same technique on a full-frame Cent and I CAN see the difference but it is much less apparent. However, I may be at the limit of resolution of the lens I was using and need to try the experiment with the Printing Nikkor...Something that will have to wait until I am moved-in as most all my equipment is now packed for the move...Ray
PS, I'm planning to rent a Canon (likely 7D) and see if I get the sharper result as SuperDave has hypothesized. The guys over on Photomacrography Forum seem to think that even with Canon the vibrations are there, and the only way to truly eliminate them is using a flash. But this complicates things dramatically since I have become very accustomed to my multiple Jansjos. Maybe my next project is an electronic one to make a flash timer box for the Jansjos. I wonder how fast the phosphors in LEDs can be pulsed...
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Moderator
United States
23522 Posts |
Keep in mind, Ray, I think only the Rebels use this feature automatically. With the 7D, it might be a menu selection - "Quiet Shot."
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Pillar of the Community
United States
548 Posts |
This improvement in sharpness is probably only possible when one uses a very sturdy stand like rpms and SuperDave use.
My stand is much flimsier, and I get exactly the opposite results. I need faster exposures to increase sharpness, not longer.
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Moderator
United States
23522 Posts |
Quote:
The guys over on Photomacrography Forum seem to think that even with Canon the vibrations are there, and the only way to truly eliminate them is using a flash. If you're going to get that obsessive about things, you'd still want to use the same technique as you did to originally eliminate the vibration above, so that the presence of light is completely disconnected from any shutter action whatsoever. That being the case, the flash is unnecessary; the Jansjos will work equally well, you'll just use a longer exposure. With that said, I think I'd cover the lens rather than the light, especially if the lens is above the lights. |
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Pillar of the Community
United States
4038 Posts |
Agreed, I think the delayed exposure technique will give the best clarity, and covering the lens is going to be the way to go with multiple lights.
I think the guys end up getting obsessive about it because they are doing stuff at even higher mag (10x, 20x) and the problems just get worse. Interesting thing is they are doing like 20 or more image stacks using StackShots to precisely step between shots. I cannot even imagine doing a 20 shot stack with flashes going on each time! The flash must also help with the setup movement during the mechanical motion of the StackShot focus rail.
This is way beyond what we need to do for coin photography, even variety shots at 3x-5x, but it is often nice to get input from other hobby areas and see if they apply to your own needs...Ray
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Valued Member
United States
158 Posts |
I believe the phrase you alluded to is "mirror lockup". It can come in quite handy for special applications such as this. On my older Canon DLSR, it is activated by way of a "custom function" in the menu. Although the new digital SLR's no longer utilize a "mirror" like the film cameras of days gone by, the term is still in use, albeit technically inaccurate.
Your mileage may vary.
Edited by CitizenPatriot
11/25/2011 10:05 pm
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Pillar of the Community
United States
4038 Posts |
I actually don't like the mirror lockup function on Nikon cameras. Although it is completely non-intuitive, you can't go into Live View mode with the mirror locked up. But in Live View the mirror is "temporarily" locked-up, at least while you are viewing. Also, and very unfortunately, mirror lockup does nothing to solve the shutter vibration problem. The shutter still has the mechanical first curtain operation, so vibration is created immediately upon shutter initiation. I just received today a Canon 20mm f3.5 macro lens, and tested it using the new delayed lighting technique (3sec shutter, lights on for 2sec). What a great little lens this is. Let me know what you guys think...Ray  Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
United States
3076 Posts |
That's quite a close up...Ray...Reminds me of your comment TO my post on lenses....and how I had it backwards......you are correct...in the full Macro state, on the bellows, the whole 15MP I can only get the first 2 digets on a Morgan dollar... I'm assuming your trust worthy 57D penny is the "Babe" shot here.....Stellar shot, didn't see the doubling before, or the green...copper spots as crisp as they are here So I have to ask...this picture is with a 20MM lens.... I am assuming, your on the bellows.....thinking....? by your results...the smaller lens.....the smaller lens lets you focus on highly focused areas of a smaller area...wear as.. the larger say 105mm lets you see the whole coin? |
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Pillar of the Community
United States
3076 Posts |
mind you my question doesn't address the vibration thing, only the lens thought...
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Pillar of the Community
United States
4038 Posts |
Gene...that's exactly right. A short lens (20mm) needs to be VERY close to the camera sensor (20mm to be exact) to focus at infinity, while a long lens (105mm) needs to be farther away (105mm). This same situation applies at higher magnifications. To get to 1:1 macro, the 20mm lens only needs to be 40mm from the sensor, while the 105mm lens must be 210mm. This is why for higher magnifications, short focal length lenses are best to keep the bellows extensions reasonable...Ray
PS...but the working distance from lens to coin of the 105mm lens is going to be longer than the 20mm, so to get lighting flexibility you want long lenses.
Overall, I've found the best compromise for bellows extension and working distance for coins is in the 75mm-105mm range. This keeps the setups small and easy to work with.
Edited by rmpsrpms
11/26/2011 10:53 am
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Moderator
United States
23522 Posts |
That's a very impressive result. Not quite the equal of your first shot, but worthy all the same.
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Pillar of the Community
United States
4038 Posts |
The problem with the Canon 20mm macrophoto lens is the working distance. 20mm is not much to work with. To help with this they designed the lens with a 45-deg front slope to allow light to get in. 45-deg is not really the optimum but seems to be what most folks recommend for macro.
I think the lens is also at the lower limit of its magnification range. I had the PB4 bellows completely closed down for this shot. The 20mm is probably at its best around 10x. Perhaps I'll try it there and see what it can do. The earlier shot was at the Nikon's sweet spot of 3x.
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Replies: 16 / Views: 3,517 |
Posted 11/22/2011 02:30 am
