Constant LED lighting V's Flash - Pro's / Con's

[Inseewincesee]

I have no experience with either at a Marco/ Micro level.

After reading many a thread/ post at this forum, I am slightly confused.

Some report that Flash is best, it apparently shows more detail in stacks [even if diffused? ], and that the ability to set fast shutter speeds is a good thing.

The other, LED lighting option I read about, was for the Metz Mecalight 480.

Which as it's numbering would suggest, has a output of 480 Lux, which I would gather would be far less than the spontaneous light output of a small [let alone several] Nikon Flash unit[s], even at 50% output, which would be my other considered purchase option.
Nikon R1C1.
http://www.nikonusa.com/en/Nikon-Produc ... ystem.html

The proposed set-up for this Macro/Micro station would be indoors, with as much vibration control as possible.
The set up being assembled is a PC driven Stackshot via Zerene stacker.
Nikon D800e, Nikon 10X objective, possibly going to 20X and beyond if vibration control is found adequate.

Would I gain anything by opting for the Nikon Flash system, over the Metz Mecalights used in the system I describe above?

I understand at extreme magnifications [50x and above] that a fast shutter speed helps get better stacks due to the 'Freezing Effect' which basically stops the effects of vibration, either at the camera end or at the more likely vibration prone 'Subject' end.

If I were to opt for a multiple Metz Mecalight 480 units, how many would I need, and at what maximum magnification would say three allow me, without vibration, obviously due to having to use a slower shutter speed because the lesser ultimate light output of the LED lights ?

If I have misunderstood this completely, which I wouldn't be surprised to find that I have.
Could somebody more experienced please explain what I have misunderstood?

[NikonUser]

I have no experience with the Metz.
I do have the Nikon R1C1. I doubt that you will need the complete system. The actual flash units (SB-R200)can be controlled via your camera set in Command Mode.
4 SB-R200s make (for me!) a perfect lighting setup. For more light 2 SB-R200s coupled with a regular Nikon SB Speedlight is ideal.
The SB-R200 and the SB Speedlights all work remotely, no wires, and are controlled via the camera; each flash can be set for the same or a different light output.

[BugEZ]

Inseewincesee,

I have been using LED lighting and slow shutter speeds for a long time. I have not used flash illumination, so my knowledge on that topic is pretty limited. But I can make a list of what I like and dislike about LED lighting...

Like:

LEDs are inexpensive and so I can construct lights to suit my purpose. I have probably manufactured 6-7 different setups most of which fit on the nose of macro lenses and microscope lenses. I buy them in bulk.

LEDs are low voltage so there is little risk from electrical shock.

LEDs are easy to control. I use simple transistor circuits and I can get parts at RadioShack (a mile away)or that I can order inexpensively on-line. A "DIY LED circuit" search turns up dozens of ways to wire them up and use them.

LEDs don't get hot, at least the ones I use. I have never gotten a burn or overheated a subject with them.

I can control when the lights are on and off I have a microprocessor controlled rig and the controller turns on the LEDs after the shutter has been open for about a half second. It regulates the "ontime" and turns off slightly before the shutter closes. Thus the shutter motion does not blur the exposure. A side benefit of low vibration and a stable rig is that I don't find much need to correct for lateral and vertical shift in my stacks. At least up to 10X. I normally have the X, Y rotation and scale alignment corrections turned off in stacking software.

Things I don't like:

Hot Pixels are a side effect of the slow shutter speeds. To fix this I use "Pixel Fixer" to remove hot pixels from my RAW images. I had to learn this the hard way, but it really helps the images and reduced PhotoShop time.

Hot Pixels (see above...)

Hot pixels... I hate them so much I had to put that in several times!

Good luck with your decision!

[chrisiieeg]

Hi All,

Apologies firstly that I might digress away from the main topic.

BugEz, I am interested if you (or anyone else for that matter) have put together (DIY) something for your own use using these new High Output LEDs, like the CREE leds.

I have one of these flashlights, and its amazing how much light and the throw this one small tiny led has.

http://www.aliexpress.com/item/Domestic ... 20375.html

I have no electronic/electrical background, but am interested in dabbling if just to make myself a "one helluva" overkill for lighting. Would you be able to share something you have created/bought/hacked together ?

Ta heaps.

Chris G.

[Len Willan]

A special welcome to another Sydney member.

This topic on lighting was partially covered in this previous discussion

Flash versus continuous lighting are we at the crossroads?.
http://www.photomacrography.net/forum/v ... sc&start=0

Best wishes on your pursuits,
Len

[BugEZ]

Below is a link to a discussion on my light. Each "bulb" in my bucket light can make about 18 lumen, though I only run it currently with about 2/3 current. Since I made the post below, the bucket light has been rewired and the number of 5mm LEDs was approximately doubled. Thus I am using 22 rows X 8 bulbs X 12 lumen which produces 2112 lumen, about 7X the flashlight in your link.

Depending on the size of your subject, you can easily get by with a much smaller light output, perhaps 3 flashlights. I made the "bucket" big enough to illuminate larger subjects (praying mantis, etc) but mostly use it for tiny flies... The stack I have running right now has the subject positioned at the plane formed by the large end of the bucket and the camera in the middle of the bucket with the microscope lens only 1cm away from the fly... This provides great lighting for the fly's eye which is my current passion, but most of the light is wasted...

I don't know how willing you are to carve up your flashlight to get to the power terminals to allow you to drive it with an external power supply. The "guts" for a 300 lumen LED "chip" can be purchased on-line from a variety of re-sellers. I have chosen to use smaller LEDs (5mm package, 18 lumen output) so that it is easier to diffuse them. Others have gone with the more powerful modules, such as you suggest. The "octolite" uses 8 powerful modules. I don't know how happy canonian has been with it since he built it many years ago.. Many use small LED desk lamps often from Ikea and position them to illuminate a diffuser around the subject. I think this is an excellent scheme (there is often wisdom in a crowd), though I have not done it.

The flashlight you suggest has a chip that compensates for droop in battery voltage as it becomes discharged. If you want to be able to twist a knob to control the light, you may wish to get LEDs with less fancy regulation. I believe the bare LED module is available without the upstream current regulator.

I use relatively inexpensive unregulated LEDs (~$ 0.06 each) so when I accidentally fry one it is not a tragedy. Still as I mentioned above I did replace all the LEDs in the bucket once (about 140 LEDs at the time so a minor tragedy...) and rewire it to add more LEDs and multiple current limiting resistors. This prevents overdriving any individual LED and reduced the current to each so I they don't end up burning out. I won't bore the forum with circuits for the drive and interface with my stacking controller but will happily share what I did off line if you wish.

Link Describing my "bucket light"

http://www.photomacrography.net/forum/v ... ght=bucket

Link describing "gated lighting"

http://www.photomacrography.net/forum/v ... hp?t=15865

Link describing canonian's "octo light"

http://www.photomacrography.net/forum/v ... hp?t=15612

And the final link I will share is the construction video of the bucket light... As you can see, it required almost no time at all!

https://www.youtube.com/watch?v=qzjLifFfYZE

Good luck!

Keith

[Inseewincesee]

Inseewincesee,

I have been using LED lighting and slow shutter speeds for a long time. I have not used flash illumination, so my knowledge on that topic is pretty limited. But I can make a list of what I like and dislike about LED lighting...

Like:

LEDs are inexpensive and so I can construct lights to suit my purpose. I have probably manufactured 6-7 different setups most of which fit on the nose of macro lenses and microscope lenses. I buy them in bulk.

LEDs are low voltage so there is little risk from electrical shock.

LEDs are easy to control. I use simple transistor circuits and I can get parts at RadioShack (a mile away)or that I can order inexpensively on-line. A "DIY LED circuit" search turns up dozens of ways to wire them up and use them.

LEDs don't get hot, at least the ones I use. I have never gotten a burn or overheated a subject with them.

I can control when the lights are on and off I have a microprocessor controlled rig and the controller turns on the LEDs after the shutter has been open for about a half second. It regulates the "ontime" and turns off slightly before the shutter closes. Thus the shutter motion does not blur the exposure. A side benefit of low vibration and a stable rig is that I don't find much need to correct for lateral and vertical shift in my stacks. At least up to 10X. I normally have the X, Y rotation and scale alignment corrections turned off in stacking software.

Things I don't like:

Hot Pixels are a side effect of the slow shutter speeds. To fix this I use "Pixel Fixer" to remove hot pixels from my RAW images. I had to learn this the hard way, but it really helps the images and reduced PhotoShop time.

Hot Pixels (see above...)

Hot pixels... I hate them so much I had to put that in several times!

Good luck with your decision!

Thanks for your response.

Just a few questions.
When you say 'Slow Shutter Speeds', just what sort of average shutter speed are we talking about here.
From posts I've read at the forum, slower shutter speeds don't cause much of a problem at up to 10X mag, but subject or camera vibration could do if shooting 20X and above.

Wouldn't more lamps / Light output reduce the needed shutter speed.

Do you shoot in 'Live View'?, reason I ask is your reported problem with Hot Pixels, and I know shooting with Live View operational is a major cause of Hot Pixels, as the sensor being constantly ON, thus heating up is causing the problem, and also causing additional noise which ends up crushing your black levels somewhat.

[BugEZ]

Inseewincesee wrote

When you say 'Slow Shutter Speeds', just what sort of average shutter speed are we talking about here.

My standard practice is to have the shutter open for 2 seconds (camera in manual, shutter set to 2 second exposure length). I run my camera on in the 2 second delay timer mode. In that mode when the shutter button is depressed (or triggered electrically by the computer) the camera pops the mirror up, waits two seconds then opens the shutter. The 2 second delay allows the "mirror bounce" vibration to decay. On my old Pentax K100 mirror bounce is appreciable. After the shutter is open, my camera/light actuator controller (which triggered the shutter) waits about a half second or so then turns on the bucket light. The bucket light switches off about a quarter second before the shutter closes so the bounce caused by shutter closure does not disturb the image. The controller then moves the bug (drives the stepper motor a few steps), waits a few seconds to allow the image to be written to the memory card in the camera, then starts the sequence over again. For convenience, I have the controller programmed to keep the bucket light on while the mirror is down and the photo is being recorded on the card. That allows a few seconds for me to peek through the camera (if I wander into the bat cave finishing the stack) so I can judge how long I have before the stack is completed. That lets me know if I have time to run upstairs and have a snack etc.... On my camera exposures longer than .25 seconds produce enough hot pixels to be a problem.

I have done quite a few studies of means of producing the sharpest images relative to shutter speed for my rig. The "gated lighting" approach is the best I have found. Once again, I have not chosen to use a strobe, but that certainly does a fine job for others. I think one of the links in my previous post discusses that a bit. I get good results at 20X, with sharpness limited by the optics, and not by vibration.

You also asked

Wouldn't more lamps / Light output reduce the needed shutter speed.

Yes. However a shorter shutter speed may push the start of the exposure closer to the "shutter open event". I tried several delays between "shutter open" and "light on" before I arrived at my current settings.

You also asked

Do you shoot in 'Live View'?, reason I ask is your reported problem with Hot Pixels, and I know shooting with Live View operational is a major cause of Hot Pixels, as the sensor being constantly ON, thus heating up is causing the problem, and also causing additional noise which ends up crushing your black levels somewhat.

My Pentax K100D which I use in the studio does not have a Live View mode. My new K5 does, but it has not been relegated to the studio and is still my field camera. Your logic does make complete sense. A stack requires about 30 minutes or so depending upon the optics used, subject size etc. The longer I spend collecting images the worse hot pixels become. A 3-5 hour stretch with a precious doli who's eyes are gradually degrading is not uncommon as the next day the specimen will be junk. I also notice that in the winter they are less of a problem than in the summer as the temperature will swing perhaps 5 deg C with the season so the camera temperature is a bit cooler. They are still a problem in the winter.

Hope this helps!

Keith

[Inseewincesee]

Again, thanks for your reply and links.

After reading further posts in the links provided, it seems there could possibly be a unknown quantity regarding when a cameras sensor actually becomes charged, and ready for use.
Not a problem for normal photography, but multiple exposures over a relatively short space of time, as occurs when stacking.... well that's a different ball game.

I suppose each manufacturer might have different ideal on where this should occur, and could have equally have changed their minds, and implementation as they have developed their DSLRs over the years.

At shutter button press ?, at Mirror lock up? at shutter release? etc.
Does anybody know for sure?

It makes me wonder what the differences might be between you Pentax, my Nikon and somebody else's Canon , for example.

And could I possibly end up suffering a similar Hot Pixel problem with my camera if used in a similar 'Lighting/capture regime' configuration as your set up?

Living in Sydney Australia the average summer temp [ when the BUGS are out and about ON MASS - Get a photo of them quickly as they will need to know what bit/stung/infested you while you are on your way to the Hospital ] is 33C- 38C.

I'm just wondering is Flash might be a better choice for me, in my situation.
Even though I would honestly prefer the ability to have a constant light source that doesn't need to rely on batteries, and the gradual slowing of a flashes recharge as the batteries lose charge.

[rjlittlefield]

it seems there could possibly be a unknown quantity regarding when a cameras sensor actually becomes charged, and ready for use.

I think you mean discharged. CMOS and CCD sensors are the opposite of Xerox-type charged plates. With CMOS and CCD, the sensor gets discharged to clear it, just before the exposure begins. Then it accumulates charge during the exposure time and for a very brief period afterward until it's read out. Most of the charge accumulation is due to captured photons, but with longer exposures some charge also accumulates due to electrical leakage. It's that latter component that causes "hot" or "warm" pixels to read as brighter than they should.

At shutter button press ?, at Mirror lock up? at shutter release? etc.
Does anybody know for sure?

I don't have access to the innards of any camera, but with mechanical shutter the logical time to clear the sensor is just before the shutter opens. If it were done at shutter press or mirror lock-up, there could be many seconds of spurious charge accumulation before the actual exposure. With EFSC (electronic shutter), the exposure effectively begins immediately after the clear operation is completed.

And could I possibly end up suffering a similar Hot Pixel problem with my camera if used in a similar 'Lighting/capture regime' configuration as your set up?

Yes, your camera would be very likely to suffer from hot/warm pixels if used with long exposures. There's no way to tell for sure except to try it, though.

--Rik

[AndrewC]

Hi All,

Apologies firstly that I might digress away from the main topic.

BugEz, I am interested if you (or anyone else for that matter) have put together (DIY) something for your own use using these new High Output LEDs, like the CREE leds.

I have one of these flashlights, and its amazing how much light and the throw this one small tiny led has.

http://www.aliexpress.com/item/Domestic ... 20375.html

I have no electronic/electrical background, but am interested in dabbling if just to make myself a "one helluva" overkill for lighting. Would you be able to share something you have created/bought/hacked together ?

Ta heaps.

Chris G.

As you are in the land down under you can easily get lots of high power leds, heatsinks and drive circuits from these people http://www.cutter.com.au/

If you want to learn how to mess with them relatively safely, google for DIY LED bikelights.

[Inseewincesee]

Thanks for the link.
I looked at the Cree LED's, then did a search for a DIY bike light tutorial like you suggested.
It seems easy enough to assemble something that would suit my purpose, but for one problem.
From what I've briefly read, those high powered Cree LEDs tend to produce quite a bit of heat, enough to need a heat sink.
In a normal set up with the lights in free space, I suppose that could be accommodated for.

I've given a lot of time to working out what possible unique problems I might suffer doing extreme macro/micro work, and come up with what I think will solve most of them.

That is a automated enclosed macro/micro photography station.

Why enclosed?
Well I live in a apartment the inner suburbs of Sydney.
I suffer from a dusty environment from all the traffic, as well a noise from said traffic, and also need to deal with any sudden wind drafts that can appear in a afternoon when a Southerly Bluster comes through [a Sydney phenomenon ], plus I wanted it light tight [from outside light ]

I can do all that cheaply and effectively using various baffles of plywood or Masonite covered in 3 pass blockout rubberized curtain lining material.
Surrounding a 20kg concrete platform sitting on large Sorbothane feet.

The only problem with being enclosed is going to be heat build up.

Now since this possibly of a Hot Pixel problem has raised it head, I'm going to have to think long and hard on possible solutions / options.

Maybe stacking in smaller slabs, shutting down to cool off, then repeat till stack is complete .... if that's possible with a PC controlled Stackshot.

[Chris S.]

Iseewincessee,

Remember that LEDs aren't the only form of continuous light--or even, to some of us, the best form. Halogen illuminators with fiber optic light guides would solve your problem nicely--just place the illuminators outside the box, and run the light guides in to where you need them. Check out this eBay item for an example of what I'm talking about--even though this particular unit is not properly matched to the voltage for your location. (The photographs in this listing happen to illustrate a nice setup. But in practice, it's often easier to purchase the illuminator separately from the light guides, which are available in single head, double head, quad head, and other configurations.)

I use three Fostec (aka Schott Fostec) Ace 1 illuminators, with a variety of Fostec fiber optic light guides. Most people would do fine with one illuminator, or princely-well with two. NB, all my illuminators have irises, which the one pictured in the above listing lacks. An iris on the illuminator makes life much easier. My illuminators sit on a shelf suspended by ropes from the ceiling over my macro rig--a convenient position, and also a configuration that nicely isolates the macro rig from the vibrations induced by the fan motor present in each illuminator.

As far as hot pixels go, I use 8-second shutter speeds, and do not find hot pixels to be a problem. Not sure why my experience differs so much from BugEZ's. I do clone a few hot pixels out of stacked images, but consider this a trivial exercise--much easier than cloning out sensor dust. I also sometimes do it in batch on pre-stacked images in Nikon Capture NX-2 raw conversion software, which also makes this task trivial. And the job could be made equally trivial with a batch job in Photoshop. Or just stack the input frames and clone out hot pixels in the stacked output.

Must admit that I'm not totally convinced that your "isolated box" approach isn't more complicated than it needs to be. Have you seen this how-to document written by Brooke Alexander and Sam Droege on the photomacrocographic techniques they use? Note pages four and five, which show their setup with and without a polystyrene cooler that they use for a light reflector. I suspect this simple approach would also offer good isolation from light, dust, and breezes. They use flash, but the approach would also work just fine with continuous light. The key elements of their approach are that they place two lights close to the subject, but facing away from it, such that no light hits the subject directly. Instead, the light bounces off the interior of the white polystyrene box, placed over and around both the subject and lights.

A few thoughts on your original question regarding flash vs. continuous light (which, as mentioned, does not have to come from LED's):

Flash solves a lot of vibration problems, and often seems like a magic wand for improving the performance of vibration-prone rigs.

Far less commonly, flash can actually induce violent subject movement. I suspect that many or most photomacrographers have little or no trouble with this. I happen to find it a major problem, and have moved more and more to continuous light. That said, I'm probably in a distinct minority: My rig is steady and easily handles continuous light; I often shoot with high-magnification (and therefore light-hungry) objectives and lighting regimes (like cross-polarization) that require a lot of light; and many of my subjects are dark (and therefore absorb lots of visible light photons and instantaneously re-emit them as infrared photons, which heat up adjacent air and "kick" the subject). Some of my subjects can only be photographed with continuous light--so far as I've been able to determine. Again, I'm surely an outlier.

Flash can easily vary a bit between exposures. Some flash units seem to vary up to 1/3 f-stop between shots; better units seem to vary about 1/10 f-stop between shots. Zerene Stacker software handles this level of variation quite easily. That said, I prefer to avoid it. (Once upon a time, my experience was quite different--was getting consistent flash exposures using flash equipment that delivered almost no variation--but it's worn out and no longer functioning. I have not been able to obtain such consistent exposures with replacement flash units.)

Continuous light is WYSIWYG in live view, whereas flash is not. In macro lighting regimes, where a few millimeters of light-source adjustment can result in big changes in photographic effect, WYSIWYG is nice.

Cheers,

--Chris

--edited typos and more typos

[enricosavazzi]

A possible solution to mitigate the problem of LED heat buildup is using a light guide (in practice, a transparent cylindrical rod) placed in front of the LED. This does not remove the heat source, but moves it 15-30 cm away. The light guide can easily pass through a slit in a curtain surrounding the stage. It involves some light loss, but the heat reduction at the exit point is very likely greater.

A possible alternative is to move the heatsink away from the LED via a heat pipe. If the LED does not generate much heat, a solid copper rod might be enough without using a heat pipe.

Another way to reduce the LED heat buildup is by turning them on only during the exposure. Let's say that they are on for 1 second and off for 10 seconds while the stepper motor moves the stage etc. This means in practice you get only about 9% of the heat generated if the LED would be always on. This also means you can do with a significantly smaller heatsink. Heat capacity of the heatsink is as important as its heat dissipation in a pulsed regime, so you cannot use a tiny heatsink, a massive (heavy) one is necessary to "smoothen out" the sudden increase in temperature of the LED die.

[Inseewincesee]

Thank you
Both Chris S
And Enrico.

I had replied to Chris S response with a long a detailed reply, between Enrico's response.
It DID appear at the site, I reviewed it several times to make sure of grammar and content.
But sadly this has either been removed [for reasons I have no comprehension about, no warning , heads up etc] or the post has just disappeared of it own accord due to some unknown technical screw up.

I remember what was posted, but in all honesty, I have a bad vibe about the reply post suddenly disappearing .

It contained nothing but questions and answers to what was talked about previously in this thread.

I'll reconsider further posting

Actually I'll Rewrite the content, save it and re post.
If it disappears again...... I always have a copy