JoeKitchen

Good to know. Thanks.

First, thank you for the responses to my previous topic. Right now I feel the ZWO AM3 with the optional counter weight would be best for me. Although the AM5 appears to have better performance, I feel it could be over kill for the focal lengths I plan on using. Plus the lighter weight and smaller dimensions of the AM3 make it more portable, which is a plus for my type of work. So now onto what to choose to power and guide this thing? For power, I was looking at the Celestron Power Tank Lithium Pro. This appears to be the best power bank that I can still fly with. Any other options that are FDA approved? For guiding, I have no idea. Any recommendations? Optimally I would prefer something that I can use to both guide and polar align. I suspect that the best placement on the system for polar alignment would differ then for guiding, or I am totally wrong on this? If those placements are different, I dont mind repositioning the guide after initial aligning in order to keep the system as compact as possible.

I did think about this, dealing with the zig zag. The panorama software I use compensates for field of view, giving me files that kind of the look like the profile of an extreme concave lens to help maintain parallax. Now whether or not I want to use this setting for stars and/or how much the zig zag would interfere with normal cropping I wont know until I actually shoot something. Insofar as the mechanical vibrations, my camera is a digital version of a 4x5 camera. There is no mirror, there is no auto focus drive, the apertures are set manually, the digital back has no moving parts. The only thing that moves is the Copal shutter. For reference, below is a 100% crop captured from a concrete pier in Key West using my 55mm at 12 seconds, ISO 140.

Thanks for the advice, but I can not turn it off. Also, I am not sure it would really matter. I don't know all of the engineering, but from what I have been told the noise from heat develops in the top portion of the diode within each pixel. Some how, Phase One, on long exposures, has their backs ignore the top portion of the diode and only records information from the bottom 2/3s. This, combined with the dark frame, allows the digital back to remove the noise from heat on a per pixel basis, but also has the effect of increasing the base ISO by one and a third stops. It is more of a physical property of the digital back. Beyond that, you would have to talk to the engineers at P1 on how this works, but I would doubt they would be willing to give any more information then that. Of course, this only works for so long. Eventually heat will travel into the remaining portions of the diodes, negating what the dark frame can do. At 68F the limit is one hour. At, say, -20F, I have been told the limit is 10 hours. Now the increase in ISO for the long exposure mode does increase noise, but noise from heat working at base ISO on long exposures is much worse. To get around this added noise from increased ISO, working on the principle that all sensors are ISOless, I over expose by one stop on long exposure mode and then pull the file one stop back in raw processing, which almost completely eliminates noise down to base ISO levels in normal working exposures. Once again, this is not a noise reduction algorithm, just me working with the inherent properties of sensors. All noise reduction algorithms are applied by Capture One (P1's raw processor) and can be adjusted by the user. Edit Just to clarify, by ISOless I mean all sensors have a base ISO of 65, assuming there is a bayer grid on it. Sensors that can only take black and white have no bayer grid and therefore have a base one stop higher. If you are shooting at a higher ISO, assuming the entire resolution of the sensor is being recorded, the sensor itself is not operating at a higher level of sensitivity. Instead the file is being pushed. Assuming your camera records the entire raw file (Canon clips theirs when it is over exposed at higher then base for some reason), pulling the exposure down in post will give you the same quality as shooting the number of stops your pulled the exposure down in ISO. The exceptions to this are with cine cameras, which usually have a base of 800 ISO. Although their sensors still have a working base of 65, cine cameras reduce the file size dramatically from the native resolution. Reduction in file size inherently reduce noise and partially "recover" the color data (from over sampling) that was lost due to a higher working ISO.

That is way too heavy for my needs.

As I said, I am a very patient man and use to being behind the camera hours on end. In my other business I photograph architecture and have been outside on many a cold day and night. The shutter vibration is almost non-existent. Leaf shutters have 6 or 8 leaves that rotate within the lens at the nodal point. As such, they only need to open a little bit to clear the incoming light. Also, each leaf as a leaf opposite it moving in the opposite direction, so movements cancel each other out. I have never had shutter vibration in my images with leaf shutter like I have with focal plane shutters. I'll be sure to share some images when I get around to getting a system. Right now things are just start to appear like they are coming back, so I am waiting for my cash flow to return. Speaking of nodal points, is it important to have the nodal point of the lens over the axis of rotation of the mount? Or are the stars so far away it does not really matter?

There would be no way to communicate between my camera and any astro software or hardware. The tracker and guide would need to be able to act independent of the camera, and just start tracking. I assume this is possible? FYI, my camera, although digital, is still completely manual with Copal 0 shutters and a analog shutter release. In the future, if I upgrade my digital back, I would be able to control a digital shutter via the computer. However, that is an expensive upgrade, and given we are just now coming off of the strikes in Hollywood, not something I am looking to do any time in the next 6 months.

Thanks. This all makes sense and not too hard to follow. Kind of makes me think about circles of confusion and DoF calculations in photography. All good stuff to know.

From what I am reading so far, forget the Skywatchers. The ZWO AM3 and AM5 appear to better fit my needs. Portable and good quality?

Nice images! I realizing guiding would be a part of these.

Good afternoon and thank you for the responses so far, and apologies for the length here. Insofar as the lenses and 35mm conversions, I was just supplying that out of rote habit. However it makes total sense that does not really matter; the focal length is the focal length. I provided the pixel pitches because in my research I read this makes a huge difference in how many arc seconds of play you can handle before image quality is hit. Correct me if I am wrong. The stars can not be visibly oval is shape. Also, for noise reduction from heat on a long exposure, my camera will automatically take a second exposure of equal length as the sensor is cooling down to map out the heat distribution and use that mapping to reduce noise from heat for that specific capture. I can not turn this function off. So effectively if an exposure is 5 minutes, it will take 10 minutes to actually process. (I am an extremely patient man by the way.) Now in terms of my usage. Backdrops are, on average, printed roughly 24x70 feet in size, but we have gone as big as 28x186 feet for a near full wrap around the set. In order to achieve this, I am creating panoramas from utilizing both panning and/or in camera shift to produce (for an average drop) ~280 MP file. Depending on the specific view I need to produce, it could be a stitch of anywhere from 6 to 14 individual images. The amount of images is dependent on both the size the directions of view in the set design. So I would want to create a library of night sky images in a similar fashion producing equally as large files in order to keep the scale accurate when using them. When producing a translight, for a variety of reasons, the night version is usually a blend of the true night image with a "night-from-day" conversion of the day image. As more and more plants become a part of the view, the amount of the true night image used goes to zero. Regardless though, I always need an applicable sky to drop in order to make it work. So this is the main reason I am looking into this, to create night sky images to drop in. With this being said, on the rare occasions where all the many conditions needed for a true Day|Night translight are met, I would prefer to actually capture the true night scene and use that since it will be more natural. (I realize the landscape and sky would be two different images in this case.) Likewise, if I were to get really nice stuff, it would not be out of the realm of possibility that a production may request a custom tighter drop of some portion of the night sky, say for a Sci Fi production. Although you may think it would better to use one of the newer LED Volumes, like used in filming The Mandalorian, or just green scene it, the fact is those Volumes are extremely expensive to use and green scenes require so much editing in post, drops are significantly more cost effective for recurring sets. So whatever mount I were to get, I would want to make sure it is suitable for tighter shots with heavier pay loads as well just in case. But, it needs to be portable. Not to mention, I am a photographer, and this is what I do in my free time as well. Last, and I can not stress this enough, as a professional I can not afford to deal with equipment that needs consistent tinkering and maintenance on my part. I mean no offense to the non-professionals here, it is just that I make my living from my equipment and I can not afford to deal with buggy stuff that is down for weeks on end. I do realize that periodic maintenance is required for all pieces of equipment, however a constant need to fix issues or worrying about a piece of equipment not working as it should is not practical. And the equipment I do use, I tend to put a lot of demands on. So a brand that is known for good service would be a plus too.

Overall budget would be in the $1500 range, give or take. I am more concerned about usability and portability right now. For $2K, if the ZWO AM5 gets me both of those, then I would consider it a good price. Edit Also, from what I have read, the other mounts I first listed all appear to require some tinkering and replacements of better bearings and grease to get the best results. Not that I would be skittish to do this myself, but I would rather save the extra expense and time by just getting a better made product.

Hello, First, thank you in advance for your advice. I am a commercial photographer that partly works in the film and TV industry producing printed backdrops and translights. As such, and for any night scenes, I need night sky photographs in my library. Currently I have a few night skies that would make sense for a city night (these were captured at a high ISO for about 8 seconds), albeit only the brightest stars are really visible in these options. They would not work well for any suburban and, especially, landscapes. Also, none of our competitors have any great night skies either, so adding stellar skies into our catalog would set us apart for that genre. So I am looking to get a tracker to allow me to capture longer exposures of the night sky to take full advantage of my camera’s base ISO (65). Also, I do fly a lot for this work, and although I would not take this on every work trip, for the ones where I will be in a more rural state or country, it would be nice to be able to fly with it as well. Of course, it would be checked. I was considering the Sky Watcher HEQ5 Pro, although I am concerned about it being a bit too large to be practical for flying. I do like the fact that it uses ball bearings instead of bushings though. I also was looking at the EQM-3 and the Celestron Advanced VX, just from a portability stand point. Although from what I read they do not work well out of the box and require tinkering with better bearings to get it up to the same level of quality. So if the portability gain is minimum at a much greater sacrifice in usage, I would not consider these to be great options. Any thoughts? Any other trackers I should be looking at? For reference, I work with a Phase One IQ260 medium format digital back (60 MP) with a sensor size of 40x54mm and a pixel pitch of 6 microns. I may upgrade to an IQ4150 in the near future, which has an 150 MP sensor of same dimensions but with a pixel pitch of 3.76 microns. I mainly use this on an Arca Swiss RM3Di technical camera with 28mm f/5.6, 35mm f/5.6, 55mm f/4.5 and 90mm f/5.6 lenses. The latter two can be used wide open. The former two really benefit from being closed down one stop and the 28mm is best used with a center filter, adding 2 stops to the exposure. This setup, combined with a Arca Swiss Cube tripod head, will weigh about 3.5 kg to 4 kg, depending on the lens. I also would like use my back on a Phase One XF camera with a 240mm f/4.5 lens and a 2x convertor, which would weigh about 5.5 kg, on the same tracker if possible for deeper sky photography. Conversions for 28mm, 35mm, 55mm, 90mm, and 240mm focal lengths to full frame 35mm would approximately be 18mm, 23mm, 30mm, 45mm, and 150mm, respectively. I almost always shoot tethered to a lap top, so adding a guide would not be an issue if it helps dramatically with the much longer focal lengths. Insofar as tripods, I use a Gitzo Series 5 Carbon Fiber Giant, which has a 80+ lb pay load. Outside of dedicated cine tripods, it is the most stable tripod I have ever used, and I’ve used many. Joe

Good Morning, I wanted to take the time to introduce myself first before I start posting. I am a commercial photographer on the East Coast working in the architectural, design and landscape genres. I work under two different businesses, the first being my name, Joseph M Kitchen Photography LLC, in which I work with architects, interior designers, construction managers, developers and hospitality professional capturing images of there projects/locations for marketing needs. The other is with Precision Backdrops, where we create printed drops and translights for the use in TV and film productions. I am looking to expand my general understanding of astrophotography to help produce better night skies for use in the backdrop side of my business. I look forward to your advice. Joe