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FORUMS Photo Sharing & Visual Enjoyment Astronomy & Celestial
Thread started 23 Dec 2017 (Saturday) 04:59
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Moon shots - stacking only a few already detailed, low ISO images - Is it worth it?

 
WestCoastCannuck
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Post has been last edited 27 days ago by WestCoastCannuck. 10 edits done in total.
Dec 23, 2017 04:59 |  #1

For me, sometimes yes, sometimes no.

The question was posed to me in another thread...... and finally I am posting examples of why I do it as often as conditions allow. (good seeing)

If I have a good clear night (VERY rare out my way unfortunately) then yes, taking the best 10 or 15 images out of about 50-70 shot get me a nicer image. Better? Well... I think so.

I shoot with a 24MP Sony A77ii + a Minolta AF400/4.5 lens + a 2X TC. I normally shoot at about 1/50 sec, ISO 50 which gives me my best results.

Here is an example from last year. (2016-11-16) The following is a stack of the 11 best out of a series of 29 shot. (I usually shoot more) I first precropped the 29 raw files with PIPP which exported them into TIF files sorted by quality. I then took the best 11 and stacked them with Autostakkert!2. The stacked TIF I then processed with Astra Image (which I use for sharpening and microcontrast) then some light adjustments and conversion to jpg in LR. This is a 100% pixel crop from the file. It is Astra Image and a well stacked file that makes the magic. For this image I used two rounds of Deconvolution - the first a medium aggressive Lucy Richardson deconvolution for deblurring, followed by a ligher touch with another round of Decovolution using "Total Variation". I added no more sharpening in LR.

There is some rotation difference in my samples... that is just because I have not tried to match my chosen view for printing quite exactly. The second image, IS the best of the 11 images from the stack according to my sorting program.

Here is a 100% pixel snip of my processed, stacked file after final adjustments in LR. (I have a nice 16X20 printed of the full view)


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Here is the single best file from the stack... processed with my meager skills in LR as best I can at a quick go. (output with 50% sharpening)

(EDIT: I have just found the original RAW - here is a processed LR jpg at 50% sharpening)

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I hope some find this interesting. :)


Feel free to add your own thoughts! (or samples or edits. Even of mine.  :p )

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MalVeauX
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Post has been last edited 27 days ago by MalVeauX. 3 edits done in total.
Dec 23, 2017 09:53 |  #2

Looking at both images, the two obvious differences that I see:

First Image: less noise (no noise), a result of stacking; but at the cost of fine detail (you lose some subtle inter-crater detail and ridge detail)
Second Image: more noise (but not bad), more fine detail in the craters and ridges

Before even worrying about stacks versus not stacking, I would instead start to explore why your ISO 50 unstacked image is so noisy to begin with (unless that is simply noise induced from sharpening method). If you're having that kind of noise at ISO 50, then you might as well be at ISO 100 or higher and having a way faster shutter to beat the seeing.

Ideally you want to be at least at 10ms to beat the seeing at higher magnifications like this. Slower than that, and you're recording more of the seeing blur.

Also, with regards to resolution, to truly maximize your detail levels at this scale, you have to match the focal-ratio, aperture and pixel size. Can't change your pixel size, but you can certainly change aperture & resulting focal-ratio. That 400/F4.5 lens has an 88mm aperture, so it's basically similar and equivalent to a basic 80mm or 90mm Refractor. That aperture size is the limit for resolution here. You can crank the magnification, but it won't get any better at this scale because the 88mm aperture is your hard limit for resolution at this scale (at higher magnification, seeing is the hard limit). The 2x TC will increase magnification, but it will not increase resolution (aperture is unchanged; focal ratio changes). The good thing about the 2x TC is that it takes the focal ratio to effectively F9. F4.5 is too fast for the pixel size of your sensor for scale. F9 is a lot closer to what it needs to be. The only way to increase your resolution and resolve more detail beyond this, requires a larger aperture, no matter how much magnification you throw at it (the aperture & seeing limit it hard).

Very best,


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WestCoastCannuck
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Post has been edited 27 days ago by WestCoastCannuck.
Dec 23, 2017 13:59 as a reply to MalVeauX's post |  #3

THANK YOU Martin for a VERY informative reply - though it raises as many questions as answers. haha The questions I must save for later.

The noise was mostly a result of my pushing the underexposed file. I normally shoot at ISO 50, 1/50 sec at F11 I see that THIS sequence I shot at ISO 50, 1/80 sec, F13. So too dark. Here is the uncorrected raw conversion with 50% sharpening. Somewhat less noise.


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MalVeauX
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Dec 23, 2017 14:43 |  #4

For exposure, use higher ISO and get a faster shutter to eliminate potential seeing/motion blur at less than 10ms, and push the histogram to the right, basically, expose for highlights and don't clip them. Then for lifting exposure, only push shadows and midtones, not total exposure. A RAW editor goes a long way for this part. Really, there shouldn't be noise even at this point at ISO 50 and ISO 100 with a modern sensor, lifting shadows not even 1 stop. I would leave it around F9, and not go smaller than that for your pixel size. You're not gaining any depth of field and you're not going to be sharper at a smaller aperture really at this scale (you effectively lose resolution as you decrease actual aperture). Ideally you want to shoot at F9 (wide open for your system). You'll get more sharpness by removing potential blur from seeing (10ms or faster) and from minor shake.

What methods are you using for sharpening? I would avoid unsharpen mask, smart sharpen, etc. I would definitely explore small subtle amounts of deconvolution and subtle high pass filter use.

++++++++++++

Noise control, here's an example at ISO 3200 from a Rebel T4i (but stacked video so noise is easily handled):

IMAGE: https://farm8.staticflickr.com/7628/26933667961_5a47d817b1_b.jpg
[IMAGE'S LINK: https://flic.kr/p/H336​8x] (external link)Moon_Mosaic_12frames_5​132016 (external link) by Martin Wise (external link), on Flickr

Each panel was processed separately with identical exposure values, quickly captured (to avoid the disc changing exposure due to a high cloud, etc) and reassembled as a mosaic for a larger resolution disc:

IMAGE: https://farm8.staticflickr.com/7296/26908090622_45cb1fce40_b.jpg
[IMAGE'S LINK: https://flic.kr/p/GZLZ​SW] (external link)Moon_Mosaic_12frames_M​SICE_Stacked_5132016 (external link) by Martin Wise (external link), on Flickr

Here's a partial web resolution version, but the point is to see how clean the detail is even at ISO 3200. The resolution of a 150mm aperture allowed me to resolve fine detail in craters and around structures on the surface that normally show up as a blur on smaller aperture instruments (aperture limits resolution). Even at this smaller scale, you see more detail even inside craters, but it's because the resolution was at 150mm aperture.

IMAGE: https://farm8.staticflickr.com/7151/26728699660_5419b82c78_b.jpg
[IMAGE'S LINK: https://flic.kr/p/GHVz​cj] (external link)Moon_Mosaic_5132016_Fi​nal (external link) by Martin Wise (external link), on Flickr

+++++++++++++++

Once you meet the limits of your aperture for resolution, you are then at the mercy of the seeing. But with lucky imaging, freezing the seeing, and captures lots of frames and only stacking a fraction of them, you can get the best least-blurry captures at high magnification, with no noise, and resolve detail in craters that otherwise don't show up on smaller apertures (due to aperture limiting resolution).

Probably one of my best seeing nights, allowed me get lucky with a 150mm aperture instrument at 3,000mm F20 (C6 SCT with a 2x Barlow) and a small sensor USB camera (ASI178MC) matching smaller pixels to the focal-ratio (I was over sampling here, should have been closer to F12 ideally, but I don't have a 1.5x Barlow, though they exist):

IMAGE: https://farm4.staticflickr.com/3857/32879254830_149a651a7f_b.jpg
[IMAGE'S LINK: https://flic.kr/p/S6qL​XY] (external link)Craters_Maurolycus_Sto​fler_03042017 (external link) by Martin Wise (external link), on Flickr

Very best,

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Davenn
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Dec 23, 2017 15:39 |  #5

WestCoastCannuck wrote in post #18524797 (external link)
...............

The noise was mostly a result of my pushing the underexposed file. I normally shoot at ISO 50, 1/50 sec at F11 I see that THIS sequence I shot at ISO 50, 1/80 sec, F13. So too dark. .

I'm not surprised ! ;-)a

I agree with Martin,

1) significantly up your ISO --- the Sony A77ii is capable of significantly higher ISO settings with out a noticeable/significant increase in noise
2) drop that f-stop down to around f9 and let more light in
3) up the shutter speed to overcome motion blur. I never shoot the moon at anything less than 100th to 120th of a sec


Dave


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Canon 5D3, 6D, 700D, a bunch of lenses and other bits, ohhh and some Pentax stuff ;)

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WestCoastCannuck
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Dec 23, 2017 21:39 as a reply to MalVeauX's post |  #6

Wow... WOW. :eek:

Martin... Thanks so much for the great info. Much of it is beyond my equipment I fear..... but wow! Your results are amazing. I have thought I might try adding another TC..... then learning to do something similar as your panels, but I am not sure I will gain anything?

Those two final shots are truly awesome - both the mosaic, and the super close up.

I just shot the little bit out there tonight..... but unfortunately seeing is horrible tonight. (A thin disc is something I have yet to capture well.... skies have never cooperated yet) I still took what you said, and tried higher ISO and shutter speed - though I need a better night for a good go.

As to what sharpening I use.... Deconvolution in Astra Image mostly. :) Though I can't add to my gear, I still hope to maximise the results from what I have - and I am already happy so I can't lose! :mrgreen:

Thanks again

Mike


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WestCoastCannuck
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Dec 23, 2017 21:41 |  #7

Davenn wrote in post #18524875 (external link)
I'm not surprised ! ;-)a

I agree with Martin,

1) significantly up your ISO --- the Sony A77ii is capable of significantly higher ISO settings with out a noticeable/significant increase in noise
2) drop that f-stop down to around f9 and let more light in
3) up the shutter speed to overcome motion blur. I never shoot the moon at anything less than 100th to 120th of a sec

Dave

Thanks for adding your comment Davenn! I am most certainly going to listen to you and Martin.  :p


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MalVeauX
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Dec 24, 2017 04:49 |  #8

WestCoastCannuck wrote in post #18525123 (external link)
Wow... WOW. :eek:

Martin... Thanks so much for the great info. Much of it is beyond my equipment I fear..... but wow! Your results are amazing. I have thought I might try adding another TC..... then learning to do something similar as your panels, but I am not sure I will gain anything?

Those two final shots are truly awesome - both the mosaic, and the super close up.

I just shot the little bit out there tonight..... but unfortunately seeing is horrible tonight. (A thin disc is something I have yet to capture well.... skies have never cooperated yet) I still took what you said, and tried higher ISO and shutter speed - though I need a better night for a good go.

As to what sharpening I use.... Deconvolution in Astra Image mostly. :) Though I can't add to my gear, I still hope to maximise the results from what I have - and I am already happy so I can't lose! :mrgreen:

Thanks again

Mike

Hi Mike,

Your equipment is fine. You'll find the resolution of an 80~90mm aperture instrument still is sufficient to get fine crater detail. You'll get more detail on a night with good seeing of course. Some times the seeing is so bad all you get is blurry fuzzy mess. Any time the moon is at Zenith position, and seeing is good, you can potentially get incredible detailed results. Your equipment is totally fine. Any dSLR that is capable of video or still images can do the job (it's even easier with inexpensive USB cameras that are cheaper though).

In your situation, adding a TC again will simply change focal-ratio and increase magnification at the cost of light gathering potential but you do not gain resolution as aperture is the same (88mm in your case) and aperture is the limiting factor here for resolution. If you keep increasing magnification, you'll notice you don't gain detail because of that. Also, if you increase magnification too much and you're already at the limits of resolving power of the aperture, you just start oversampling and so it's actually even more blurry than it would have been for the scale. I would keep it as you have it, 88mm at F9 basically, that's a good focal length & focal-ratio for a non-tracking full disc setup.

You'll get more gains from changing how you expose and process. You have the gear already.

+++++++++++++

Here's an 80mm F7.5 instrument, very similar to what you're using (smaller aperture, less potential resolution, but physically longer at 600mm). I put a 2x barlow on it to make it an 80mm aperture (1200mm focal length) F15 instrument. I paired it with a small sensor USB camera, with a pixel size that matches up with approximately F12, so the F15 is very close to it and so critical sampling for scale will be close to ideal. Even though the 80mm aperture is the limit here for resolution, with good seeing, and good scale matching, you can still achieve great detail. This is why I keep referring to pixel size and focal-ratio as a point when talking about scale and sampling. You can get a lot out of smaller instruments. It's all about tweaking everything to be in your favor.

For processing, I stack, but I avoid oversharpening, wavelets in Registax are ok, but deconvolution seems to be a little better, and subtle high pass filters do a good job to bring up ridge detail without clipping highlights.

Crater detail resolved in Petavius (the line, central projection, etc):

IMAGE: https://farm6.staticflickr.com/5695/31403940815_c6f3b4f68f_b.jpg
[IMAGE'S LINK: https://flic.kr/p/PR4p​vr] (external link)MoonMosaic_12032016_Pe​taviusCrater (external link) by Martin Wise (external link), on Flickr

And a few of those captures then combined as a mosaic:

IMAGE: https://farm6.staticflickr.com/5476/31288403171_cf6b8f5e42_b.jpg
[IMAGE'S LINK: https://flic.kr/p/PERf​c6] (external link)MoonMosaic_12032016 (external link) by Martin Wise (external link), on Flickr

Very best,

My Flickr (external link) :: My Astrobin (external link)

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WestCoastCannuck
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Dec 24, 2017 12:13 as a reply to MalVeauX's post |  #9

Thanks again Martin. Fantastic, inspiring example! I think I will keep an eye out for an inexpensive smaller sensor camera that I can adapt to my lens setup - I was thinking something like a Nikon 1j5 when a used one comes up cheap enough. It would need to be something with an interchangeable lens - so an adapter would be available.

In the mean time.... my A77ii IS capable of 1080P video. Is that something worth exploring? I currently shoot raw files, convert to TIFs and stack those.


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MalVeauX
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Dec 24, 2017 12:38 |  #10

WestCoastCannuck wrote in post #18525460 (external link)
Thanks again Martin. Fantastic, inspiring example! I think I will keep an eye out for an inexpensive smaller sensor camera that I can adapt to my lens setup - I was thinking something like a Nikon 1j5 when a used one comes up cheap enough. It would need to be something with an interchangeable lens - so an adapter would be available.

In the mean time.... my A77ii IS capable of 1080P video. Is that something worth exploring? I currently shoot raw files, convert to TIFs and stack those.

Heya,

1080p video could be useful for things like planets and higher magnification shots of crater detail (not full disc). You really don't need any of these methods for full disc shots. But higher magnification shots where you're at higher resolution with a large aperture instrument with good seeing, that's where video comes in. Also, it depends on how your sensor handles 1080p video (as in, is the full sensor being used and samples it down, or is the sensor reduced to only using enough active pixels for 1080p, etc, I don't know how that sensor works for that purpose, it would matter though).

For a cheap good USB3 camera for lunar imaging, etc, I'd look for a ZWO ASI224MC (color sensor) or ASI178MC (color sensor) or ASI178MM (mono sensor, ideal) or ASI174MM (mono, ideal). They're fairly inexpensive, from $250 to $400 used. The 174MM is closer to $450~500 used. New prices are of course whatever they are these days. But they're still cheaper than dSLR/mSLR and much better suited to lunar surface detail imaging via video. But to even begin using these at high magnification with larger aperture instruments, you'd want to be using a tracking mount ideally so that you stay on target for the duration of the capture. So while the cameras are not expensive, and the instruments are not expensive (a 1500mm F10 C6 SCT is only $399 new), the tracking mounts are expensive, big, and heavy.

So unless you're moving that way anyways, I'd stick with d/mSLR and just play around with tweaking things for scale and focal ratio based on pixel size so that your sampling is ideal and then just look for the best seeing nights at Zenith position and capture as much as you can.

The above mosaic I made the first time was done with a 7D using it's video capture mode, the output files I limited to 1024 pixels on the long side, then I merged them and you can see the detail there because of the scale and sampling match. You can certainly do better probably with your more modern camera.

These days, I only use USB3 cameras made for this type of stuff and I shoot in monochrome only now (I use an ASI174MM). They're much cheaper than terrestrial based still shot cameras and much better for teh task. But, I'm usually using a 120mm or 150mm aperture instrument and high magnification, on a big tracking mount. Just a different approach from a tripod & long lens, which is where we all start!

Very best,


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WestCoastCannuck
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Dec 24, 2017 15:44 |  #11

MalVeauX wrote in post #18525482 (external link)
Heya,

1080p video could be useful for things like planets and higher magnification shots of crater detail (not full disc). You really don't need any of these methods for full disc shots. But higher magnification shots where you're at higher resolution with a large aperture instrument with good seeing, that's where video comes in. Also, it depends on how your sensor handles 1080p video (as in, is the full sensor being used and samples it down, or is the sensor reduced to only using enough active pixels for 1080p, etc, I don't know how that sensor works for that purpose, it would matter though).

For a cheap good USB3 camera for lunar imaging, etc, I'd look for a ZWO ASI224MC (color sensor) or ASI178MC (color sensor) or ASI178MM (mono sensor, ideal) or ASI174MM (mono, ideal). They're fairly inexpensive, from $250 to $400 used. The 174MM is closer to $450~500 used. New prices are of course whatever they are these days. But they're still cheaper than dSLR/mSLR and much better suited to lunar surface detail imaging via video. But to even begin using these at high magnification with larger aperture instruments, you'd want to be using a tracking mount ideally so that you stay on target for the duration of the capture. So while the cameras are not expensive, and the instruments are not expensive (a 1500mm F10 C6 SCT is only $399 new), the tracking mounts are expensive, big, and heavy.

So unless you're moving that way anyways, I'd stick with d/mSLR and just play around with tweaking things for scale and focal ratio based on pixel size so that your sampling is ideal and then just look for the best seeing nights at Zenith position and capture as much as you can.

The above mosaic I made the first time was done with a 7D using it's video capture mode, the output files I limited to 1024 pixels on the long side, then I merged them and you can see the detail there because of the scale and sampling match. You can certainly do better probably with your more modern camera.

These days, I only use USB3 cameras made for this type of stuff and I shoot in monochrome only now (I use an ASI174MM). They're much cheaper than terrestrial based still shot cameras and much better for teh task. But, I'm usually using a 120mm or 150mm aperture instrument and high magnification, on a big tracking mount. Just a different approach from a tripod & long lens, which is where we all start!

Very best,


Thanks again Martin! Great advice. :) I enjoy using what I have, and have so far resisted the temptation to start on the "dark path". haha. Given 3 kids and little time, it really does not make much sense for me - especially since what I do already when the seeing is there takes a LOT of time as it is! And the moon is only one of many photographic interests - most of which get little time these days. (other than my love of candid kid shots!)

I certainly see myself with dedicated gear one day.... but not for the foreseeable future! haha

Very best Regards

Mike


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Pagman
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Dec 24, 2017 18:32 |  #12

Hi, I am confused about Aperture instrument are you on about the Aperture of the lens eg with my nikkor 300mm it is an f4 lens.

P.


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MalVeauX
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Post has been last edited 25 days ago by MalVeauX. 2 edits done in total.
Dec 25, 2017 04:57 |  #13

Pagman wrote in post #18525668 (external link)
Hi, I am confused about Aperture instrument are you on about the Aperture of the lens eg with my nikkor 300mm it is an f4 lens.

P.

Aperture on camera forums (and on cameras themselves) is commonly used as a misnomer to actually talk about focal-ratio. Aperture really refers to what it is: the opening into the instrument (be it a lens, scope, roll of paper, etc). Focal-ratio represents the aperture & focal length ratio (example, 400mm focal length at 80mm aperture is F5). But the physical aperture of the lens/scope is constant (usually, at least the front opening that is mostly referenced when referring to an instrument's aperture) unless you stop it down (which can be done at the opening of the instrument, or within it, such as with a lens and it's electronic aperture control, or by physically covering a portion of the opening into the instrument, which is common with large scopes).

Your Nikkor 300mm F4 has a 75mm aperture. The physical opening to your lens is 75mm diameter. That's what forms the ratio with the 300mm focal length resulting in an F4 focal-ratio.

Very best,


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Tareq
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Dec 25, 2017 21:50 |  #14

Soon i will focus on the moon, once i get the scope as i said, i got the camera, new model, and Barlow maybe sooner or later too, then only left or missing is the scope, and i am having so so big discussions in many sites for which scope i should get, not for the moon, but the moon is an easy target anyway with any scope small or larger.


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Pagman
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Dec 25, 2017 22:06 |  #15

MalVeauX wrote in post #18525835 (external link)
Aperture on camera forums (and on cameras themselves) is commonly used as a misnomer to actually talk about focal-ratio. Aperture really refers to what it is: the opening into the instrument (be it a lens, scope, roll of paper, etc). Focal-ratio represents the aperture & focal length ratio (example, 400mm focal length at 80mm aperture is F5). But the physical aperture of the lens/scope is constant (usually, at least the front opening that is mostly referenced when referring to an instrument's aperture) unless you stop it down (which can be done at the opening of the instrument, or within it, such as with a lens and it's electronic aperture control, or by physically covering a portion of the opening into the instrument, which is common with large scopes).

Your Nikkor 300mm F4 has a 75mm aperture. The physical opening to your lens is 75mm diameter. That's what forms the ratio with the 300mm focal length resulting in an F4 focal-ratio.

Very best,


Hi there seasons greetings,

Guess it doesn't matter much but my lens has a 82mm front element, dont think it would make any difference compared to the 75mm you quoted?

P.


Nikon D7100, Nikkor 300 f4 IF ED :-)

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