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02-22-2013, 10:13 AM - 1 Like   #1
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The MaQro Qlub!

There've been several threads on MaQro, but I think an ongoing thread would be useful (and would take a little pressure off the very busy Reach thread).

All kinds of close-up work on the Q are welcome in this thread. Doesn't have to be extreme, just larger than life in the final result.

Going to start with a very boring comparison. This is two separate shots with the Sigma 70/2.8 macro, one on the Q and one on the K-5, at various crops. With the K-5 the lens was at MFD (just over 1:1 magnification) and with the Q the magnification was accordingly lower; I was attempting to get the same scale of pixels to subject and got fairly close but not exact, as you can see. I did focus and aperture bracketing and picked the best shot for each camera. I matched exposure and color as well as I could, and applied the same sharpening settings to both. No NR.

25% crops:





50% crops:





100% crops:





Some observations and thoughts:

On the K-5 all apertures from f/2.8 to f/8 were very good, with f/5.6 the best and f/4.0 close behind. On the Q the extremes from that range were not so good; f/4.0 was the best aperture with f/5.6 pretty close. So the K-5 has the advantage in range of usable apertures with this lens.

Working distance (with no lens hood, measured from end of lens barrel): about 20.5 cm vs. 6.3 cm: huge advantage for the Q.

Depth of field: my new macro rail has a micrometer head so I can make very precise camera movements, and have a pretty good idea of the depth of field, although I haven't tried measuring it as such. But clearly the DOF is somewhere around 3 times Update: after a better test, and comparing the best aperture on each camera, it's really more like 2 times greater with the Q in this comparison.

Resolution: here's where you pay the price; even at a 25% crop the K-5 shot is clearly sharper. For uncropped shots at typical web sizes there won't be as much difference, but for cropping and/or enlarging final images beyond this the Q is at a definite disadvantage.

So, when comfortable working distance and/or greater DOF is important, and especially if you don't crop much, the Q wins. Working distance isn't just about whether or not you scare the bugs away; it also affects the difficulty of getting the camera into position without bumping into things, and the lens getting in the way of subject lighting. For maximum resolution under controlled conditions, stick with the DSLR.


Last edited by baro-nite; 02-22-2013 at 11:25 AM. Reason: correction
02-23-2013, 08:30 AM - 1 Like   #2
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This isn't a comparison as I have no way to get an equivalent magnification with this lens on the DSLR. Sigma 70/2.8 again, this time at MFD (just over 1:1) on the Q. Uncropped.


Salt

Again, lens down one stop. 26 images stacked in ZereneStacker, 0.25mm slice depth. The Sigma 70/2.8 has no aperture ring, so there is no way I can get much beyond 1:1; score another point for the Q. Still another advantage: while I do have other rigs that will get to 3:1, I would need to stack at least twice as many images because of the smaller DOF, so this was quicker both in capture and PP. And maybe less wear on shutter mechanisms, although I do wonder how many mechanical shutter clicks the K->Q adapter is good for. And any 3:1 rig other than the Canon MPE-65 is going to be full manual, whereas I used Av mode for this set.

So once again, while it might not be the best in terms of resolution and dynamic range, the Q as a maQro Qonverter gives you convenience and options.
02-24-2013, 04:45 AM - 1 Like   #3
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Here's my Bellows Rig for a Pentax Q, an amazing piece of kit, everything from infinity focus (I can use it as an M42 adapter) to around 5X magnification, which, with the Q's tiny sensor is less than 1mm filling the frame!

[IMG] [/IMG]

It's winter here so finding small subjects is difficult, but the Wallflowers always try the hardest,

First the overall shot with the bellows retracted

[IMG] [/IMG]

A little closer.




And a shot of a budding Wallflower, the 'flower' is around 1.5mm across, some movement in this shot because of high ambient light - see below.

[IMG] [/IMG]

Still not at the end of the focus rail with this shot, I could go closer, but not hand holding. Just keeping the subject in the frame is a bit of a lottery when you have this magnification and your still over a foot away.

The TTL flash is important as the short flash duration (1/1000th of a second or faster) effectively becomes your shutter speed if the ambient light is low, All these shots are hand held. Even with the closest one I am around a foot away from the flower. In the last shot you can see some blur caused by the sensor recording for 1/13th of a second, I want little or no ambient, it works best in near darkness using a torch to get focus. Often all you need is the pop-up flash.

I have set the Q so that the pop-up flash doesn't fire when down for this rig, (Custom Menu, item 10 'Flash When Retracted' to option 2), the idea is that off camera flash gives some modelling. The flash will still fire when popped up. By default both flash fire.

The Q never ceases to amaze me, if I put my 300mm M42 lens on this rig I could photograph the Moon, so everything from Astro to near Micro in one rig! Amazing! Can't do that with my K5.

Chris
02-24-2013, 06:35 AM   #4
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Chris: I saw your bellows rig in another thread and I am extremely jealous. I did some searching but haven't found any D-mount bellows units -- where did you get yours?

02-24-2013, 11:41 AM - 1 Like   #5
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Hi baro-nite

They aren't commercially available you have to make your own.

A cheap bellows off eBay was my starting point. The D mount is simply bored out (to around 20mm) and bolted to a thick washer I turned from black Delrin, an engineering Acetyl plastic, and sized to fit the bellows mount diameter, 45mm diameter for my bellows. This 'washer' is a tad over 6mm thick, you could make it from wood, aluminium or whatever. You might even be able to make it with a hole saw.

At first I was trying to keep the bellows lens flange and the Q lens flange as close as possible so I would keep infinity focus, the D mount was too close to the front 4 way function knob and I could focus passed infinity! After some research I realized that all I needed was to keep the lens flange distances at or below 35.26mm and I would keep infinity focus on the M42 lens.

The cheap small single rail bellows you can see, which is in keeping with the size of the Q, is small and only has a 110mm rail, which is all the Pentax Q needs, the more usual 35mm bellows are longer than this, with a Q you would be well into the Micro world with their length of bellows. I don't see many on eBay this small. When you do they are usually cheap, I got two for 15 a few years ago, the other is used with my m4/3 cameras, this one has a split in the bellows which doesn't seem to effect it too much as I rarely need to use the maximum length.

Chris

Last edited by ChrisJ; 02-24-2013 at 11:49 AM.
02-24-2013, 11:51 AM   #6
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QuoteOriginally posted by ChrisJ Quote
They aren't commercially available you have to make your own.
Excellent project and description -- thank you!
02-24-2013, 12:28 PM   #7
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Great setup Chris .. very versatile!
Just to add, with some bellows you can remove the mounting flange and potentially replace it with a custom Q adapter to maintain infinity.
I'm curious about your 'TTL' flash setup .. my impression was that your shutter speed will be 1/13 and that (whatever) flash is used in manual mode (prob something like f/8-16) (or possibly flash's own auto setting) .. that the Q does not have any TTL capability?? Please elaborate.. thx!
02-24-2013, 02:04 PM - 1 Like   #8
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The Q does have P-TTL capability with any dedicated flash such as the AF-200FG shown which is how I use it.

The idea is you use a low ISO and a small aperture, the area that the lens can see is small and will not reflect much light so 90%+ of the exposure is the light from the flash, then the 1/13th of a second scan time doesn't make any difference as so little of the ambient light is part of the exposure so it doesn't register on the sensor.

Then the flash duration is effectively your shutter speed. At these low powers (because you are so close) the flash duration will be much faster then 1/1000th (can be as fast as 1/50,000th) of a second, fast enough to freeze any camera movement from hand holding. That's how the above shots were taken.

In the third one there is some slight smudging of the brighter parts of the flower (the yellow area on the right hand side of the flower), if the ambient had been darker (this was shot in overcast daylight, early afternoon) that smudge wouldn't be there as it would have been dimmer, if you see what I mean.

Not wanting to 'teach Grandma to suck eggs', I hesitate to say how flashguns (strobes) work, but for the uninitiated the flash tube always works on full power, the different outputs alter the flash duration, even at maximum power it will be around 1/1000th of a second, at lower powers the flash reduces the flash duration, on minimum power it can be as fast as 1/50,000th of a second. With TTL the camera sends a signal to the flashgun to quench the flash when it has seen enough light. It fires a pre-flash and from this info it sets the timing of the flash duration automatically.

There are some advantages in using a manual flash where you can manually adjust the output, and therefore the flash duration.

When taking a flash picture you are taking two exposures simultaneously, the flash component and the ambient component. With manual every thing, manual mode on the camera and manual flash you can alter both exposures independently, it works like this.

ISO and Aperture control both the ambient and flash components the same.

Flash to subject distance and flash power controls just the flash component.

Shutter speed controls just the ambient, shutter speed is always slower than the flash duration so shutter speed has no effect on the flash component.

We can use this, when taking Macro images the flashgun to subject will always be the same, the focus sets it, when it's in focus the distance from the subject must be the same as every other shots at these settings.

We know the 'shutter time' is 1/13th of a second, by using a small aperture, low ISO and having dim conditions we can eliminate the ambient to be too low to record on the sensor, so the only light the camera sees is the flash. By having that on low power we have a faster flash duration, you will have to set the flash output to get a decent exposure, but once set it will always be the same as long as you don't change any of the settings, with TTL we place the flash close to the subject then the camera will automatically set a low power and hence rapid flash duration. Easily fast enough to freeze any of the inevitable camera movement. The advantage with manual flash, apart from price, is that they will usually have lower power settings than TTL flashguns do, some as low as 1/256th power.

You can use this technique in normal photography too to get totally black backgrounds which is how this was taken.




Then slowing shutter speed will increase the brightness of the ambient, you have total control.

Sorry for going (slightly) off topic.

Chris

02-24-2013, 02:34 PM   #9
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QuoteOriginally posted by ChrisJ Quote
Here's my Bellows Rig for a Pentax Q, an amazing piece of kit,
Looks like a great setup and fun to build I will have to add it to my list to things to do.

Thanks

Hans
02-25-2013, 09:30 AM   #10
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I was confused abut the talk of "TTL", which is actually P-TTL - a different flash metering technology. Only (newer) P-TTL flashes will meter the flash through the camera. As I have the older AF200T (an actual TTL era flash) I can only use it in M mode where I can vary the power 1/8 .. full - very handy. It also has two A modes of it's own via a built-in flash sensor (not useful for macro).

Thanks for the explanations Chris, I'm sure many will benefit from reading it!!
03-03-2013, 03:26 PM   #11
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I posted this elsewhere but thought it should be in this thread.



50mm Russian Lens w/ Toilet Paper Extension tube (25mm)

Photo of the hackle on a fly fishing lure.

Stock flash extended was on
03-03-2013, 03:59 PM   #12
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QuoteOriginally posted by Quij Quote
50mm Russian Lens w/ Toilet Paper Extension tube
Going all high-tech and expensive, aren't we?


Nice work!
03-03-2013, 04:08 PM   #13
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QuoteOriginally posted by panoguy Quote
Going all high-tech and expensive, aren't we?


Nice work!
Thanks!

I wanted to see if I should invest in an extension tube for this lens because I found a whole set of them but they have to ship from Ukraine. Haha, I will continue testing until the gorilla tape ceases to keep it all together
03-03-2013, 05:01 PM   #14
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QuoteOriginally posted by Quij Quote
Photo of the hackle on a fly fishing lure.
Excellent! Great composition, not to mention creative use of equipment.
03-03-2013, 11:03 PM   #15
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Another shot with the same set up as before

Same distance with 01 Prime
50mm lens with 25mm extension "tube"
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