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1
EOS Bodies / Re: POLL: How many mp do you want anyway?
« on: January 30, 2015, 02:43:34 PM »
I wonder: ???
If many here want 36 megapixel, why D800, D810, A7r are not big sales successes? ::) :-X
I'd argue the D800 series is a success, but no use if you have a ton of Canon lenses. How many are willing to either convert or go multi-system with Nikon? You need deep pockets to do that. The Sony suffers from the "not enough lenses" problem with any new mount. MP count isn't the only problem people have.


Personally, before I give an answer to "how many MP", I have to say my answer will rather require a different mindset than is current. I'd say, for an APS-C sensor, I'd like a minimum of 150MP. For the "why" I'd argue not every pixel matters. To me, the bayer pattern sensors have always been a cheat by the manufacturers, but as almost everyone does it, it cancels out. In essence we're not sampling RGB at every single point, and the software has to make it up, sometimes better, sometimes worse. By having a ton of pixels, particularly more than you ever need for output, you get more colour resolution. What about noise you say? Well, noise isn't noise. It will have characteristics. By downsampling to your actual output size, you keep the increased colour resolution and reduce the higher spatial frequency noise. 150MP is roughly what is easily attainable by scaling up compact camera sensors from a few years ago. By today's technology it could be much higher.

Obviously the way we handle this data may need a different strategy also.

The Foveon type sensor doesn't have that problem, but comes with a load of different problems.

2
Photography Technique / Re: Which eye do you use?
« on: January 27, 2015, 10:56:15 AM »
Interesting one this... I tried a similar question on another forum and results came back near enough 50/50. Will be interesting to see if that is the case here once the numbers go up some more.

I tried to correlate it with handedness and basically there didn't seem to be any pattern.

3
Canon General / Re: Photographer Petitions Canon for Left Handed Camera
« on: January 27, 2015, 10:09:26 AM »
My first SLR was a lefty camera. An Exacta Varex,  and as Canon makes cameras for astro photography, why not make a lefty camera?
I bet there are far more left handed photographers than astro photographers.
Mind you, I bet that there a few left handed astro togs out there too!

The hardware modification to make a camera more astro friendly is, more or less, change one piece of filter glass. The effort required to make a full "leftie" camera is many orders of magnitude more complicated.

Also, pretty much all astrophotography is done with the camera on a mount of some kind. If you're at all serious, you'd use an external release or USB connection to control the camera. Handedness of the camera then becomes irrelevant in this usage case.

4
Canon General / Re: Photographer Petitions Canon for Left Handed Camera
« on: January 26, 2015, 08:55:12 AM »
I've always wondered if this is something that could be catered for by the use of battery grips. Yes, it would increase size and bulk, and limit access to the connections. I'm guessing it probably wouldn't be really economic to also sell a native left handed model of everything, so an add on left handed grip might be a workaround.

5
Landscape / Re: Deep Sky Astrophotography
« on: January 11, 2015, 09:35:21 AM »
Here's my attempt of Lovejoy C/2014 Q2 last night. My Sigma 300 is lent out so I made do with a 150mm macro instead.

Equipment: Canon 7D2, ISO1600, Sigma 150mm f/2.8 macro at f/2.8, Astronomik CLS CCD filter, 161 x 30s exposures. Took more but rejected a load due to cloud. Tracking background stars unguided with lousy polar alignment.

Processing: Starting with PixInsight, flats, star align, comet align, stack, stretch, DBE (I messed up that order, should be done earlier), curves, photoshop.

Above is only the comet aligned stack. I've yet to do a star align stack.

I've tried to optimise viewing for the tail in this image. My local light pollution is rather rubbish.

6
EOS Bodies - For Video / Re: 1100D video for astro work
« on: December 28, 2014, 08:43:24 AM »
In what way can the moon damage the sensor? Light bouncing off it isn't that different from daylight levels.

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EOS Bodies - For Video / Re: 1100D video for astro work
« on: December 27, 2014, 10:29:14 AM »
Note the question was for video imaging, not stills. Also the 450D has had its day. I've used both the 450D and 600D for long exposure astrophotography, and the 600D output is visibly better. Sensor generation trumps pixel size there.

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EOS Bodies - For Video / Re: 1100D video for astro work
« on: December 27, 2014, 08:47:33 AM »
I've taken video of the moon with the 600D before. I found the mov format to be a pain since most astro software handles avis. Also the video is lossy compressed. I note the 7D2 now has the mp4 option which is a bit easier to handle, but don't know when they might have added this to other models. Dedicated astro video cams can output raw video so you get better quality stills out of it. I think someone made a picture style before which was flatter and more neutral which could help with later processing.

On that note, with planets, unless you have seriously big optics, they are still tiny on sensor. A bigger sensor is wasted. For example, the camera I was using is "only" 640x480 with similar pixel size to the 18MP APS-C Canon sensor. You can easily fit Jupiter on that with 6m focal length. I was trying between 4m f/20 and 6m f/30 and there isn't much in it quality wise. Yup, could use a bigger scope :) Other planets are going to be smaller! Also with a dedicated astro camera, you can run at higher frame rates to increase your chances of getting good moments.

For a rough idea, below are with the astro imaging cam, not DSLR, but gives an example of what you could expect size wise. They are 100% crops. Left is my first and only serious Mars attempt though 6m f/30, and right is Jupiter at 3m f/30 (I was testing out a new scope at the time). That's with 200mm and 100mm aperture optics. If you can go bigger, there is more resolution potential.

Back to DSLR output, I don't think I ever bothered going through processing the moon video I took with the 600D, but I would say the moon would be a better choice to play with in this case.


9
Lenses / Re: Any ideas on getting good focus when shooting thru glass pane?
« on: December 23, 2014, 05:47:29 PM »
Is the focus off, or is the image distorted? If the glass isn't perfectly flat, it will lead to distortions which both throws off the focus and also negatively affects the image. Only workaround is to move around and try shooting through a different bit of glass. On that note, keep as perpendicular as you can to the glass. Tilted glass will cause an effect like a prism.

Stopping down can help mitigate those effects to an extent.

10
Lenses / Re: With a new 100-400L, is the 28-300L Next?
« on: November 29, 2014, 12:41:30 PM »
I would think a 28-300 non-L would be a possible candidate, especially if they want to expand full frame more into the (relatively) affordable mainstream.

11
Photography Technique / Re: Extreme macro question
« on: November 23, 2014, 05:29:42 AM »
If your lens supports it, you can use a teleconverter. I prefer this over extension tubes as you retain working distance and focus range.

Also it is untrue that extension tubes wont degrade image quality. Well, it may not be noticeable at moderate amounts, but you're pushing the lens out of its designed operating region. For example, if you try this on the 50mm f/1.8 you will find massive field curvature quite quickly. Combined with the quick loss of working distance I'm not a particular fan of this approach, but certainly it is a low cost option.

The MP-E65 does what it is supposed to, but lighting it has always been the biggest problem for me, and that would be an area you would need to put effort into.

If you want serious magnification, you can always buy a microscope with DSLR adapter. These adapters aren't just mechanical, but better ones include corrective optics. With my particular microscope, I get horizontal field of views of about 1.2mm and 0.3mm with 10x and 40x objectives respectively on APS-C sensor. In lens equivalent magnifications, that would be about 19x and >70x! Of course the subjects will be limited here, as you will have near zero working distance and depth of field! I really should get better at focus stacking...

12
EOS Bodies / Re: Canon 7D II sensor measurement
« on: November 18, 2014, 05:27:11 PM »
That's a new site to me. The obvious question is, do their scores make any more sense than, say, DxOMarks? I had a poke around the site, and the description of the subscores is a bit vague at best. Even DxO explain it better than they do, but the weighting here does seem more rounded.

13
Lenses / Re: Advice needed on possible 100-400 L Lens Trade
« on: November 15, 2014, 01:40:20 PM »
I'd echo the above, check the zoom action is smooth and doesn't stick/jump. Also look through the viewfinder when doing so. I fear my 100-400L I had since new is wearing out from heavy use, and the zoom isn't smooth any more.

I previously had a used 35-350L which is also pump action, and that suffered even worse. At least I got that from a dealer so I could return it.

14
What's the "f" number?
Just looked it up. They decided on f/15, giving a focal length of 450m.

I've tried planetary imaging with 4 to 6m focal length optics before with moderate success, as the collimation wasn't right. I have to wonder what sort of images might be possible if they pointed the TMT at closer subjects such as those.

15
EOS Bodies - For Stills / Re: Is the 7D MK II Really Selling Well?
« on: November 04, 2014, 02:37:10 PM »
Without actual sales numbers we're just guessing.

I tried to look at UK dealers, but most don't have real time stock info so it is hard to tell who has what.

Personally I will buy one, but I'm not buying right away. In the UK, generally new kit sells at MRP/RRP/whatever RP at launch, and drops gradually over time. We don't seem to get instant discounting like other countries. I might bite when it drops 10-20%.

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