Need advice
8 views
Skip to first unread message
adhi M
May 5, 2024, 2:54:14 PMMay 5
to croydonastro
Hi all,
I'm very new to astro photography but very interested. I have a sony mirrorless a6400 camera with Vivitar 28mm F2 lens and a tripod. Can you suggest
1. Easy targets for a beginner like me
2. Places in and around london to capture
3. Low budget equipment to get started with, if any
Basically, Requesting some guidance to get started as beginner.
Thank you!
William Bottaci
May 6, 2024, 7:37:45 AMMay 6
to croydo...@googlegroups.com
Hello Adhi
From the information given, assuming no tracking equipment (see later) you can start by taking 'long' exposures of anywhere in the sky, I recommend the Milky Way region, Cygnus this time of year, Cassiopeia later. Don't worry about where in the sky to start, there are stars everywhere; best to sort out the method as the camera can be pointed most places at any time. You should aim for 45º upwards at least.
As for the darker sky locations, roughly where do you live and how can you travel? For the trial you can start anywhere. I recommend around rather than in London, but later.
You have all you need to start, and the flip viewscreen will help.
The exposure time should be the longest before star trailing starts to show, and background light pollution too. As a guide for your equipment for star trailing try around 16 seconds maximum, but start from several of each of the following before going to the next exposure: 2, 4, 8, 16 seconds, so say 10 exposures of each period, then look at these carefully and decide which look more pleasing.
As a rule it's 500 divided by the focal length of the lens in mm. So 500/28 = ~ 18 seconds. Some people use 400, others 300; the number for you will be determined by your trial.
Take care of the noise/ISO level; just because the camera has 32000 ISO in Manual Mode does not mean the image will look acceptable; you should experiment. I recommend starting at 320 or 400 ISO for your camera, but the optimum value ultimately depends on your light pollution, post processing and exposure time. It seems like the maximum is 1600 or 3200 ISO but for these you really need dark skies and optimal processing (by an expert :).
Needless to say you absolutely must shoot in Raw mode (Raw, 16 MP, 4000 x 4000) don’t even think of only jpeg (long story, all true, don't start me :).
If you don't have a Raw file processor, send me a few images, I'll return with workflow explanation, and there are several free programs that are excellent, in results, but may be a bit involved to use. More on these later.
There is also noise reduction that can be performed, all easy, but the best thing is to make any kind of start, and we'll all look forward to seeing the results.
If you can afford it you should seriously look at getting the Omegon Mount Mini Track LX2 (~£170) as then you can stack multiple images and get results you'll want to mount on a wall. I use one, remarkably accurate, all the more so with 28mm, and you won't need to reposition it for the whole hour. Has good green credentials too.
Whilst this allows longer exposure time, in your case that probably won't be necessary, but it'll pay dividends with reducing noise, well worth doing when you see the results.
Remember not to be disappointed with any initial result as lots of things can be done to guide you along the way.
Regards, William
From the information given, assuming no tracking equipment (see later) you can start by taking 'long' exposures of anywhere in the sky, I recommend the Milky Way region, Cygnus this time of year, Cassiopeia later. Don't worry about where in the sky to start, there are stars everywhere; best to sort out the method as the camera can be pointed most places at any time. You should aim for 45º upwards at least.
As for the darker sky locations, roughly where do you live and how can you travel? For the trial you can start anywhere. I recommend around rather than in London, but later.
You have all you need to start, and the flip viewscreen will help.
The exposure time should be the longest before star trailing starts to show, and background light pollution too. As a guide for your equipment for star trailing try around 16 seconds maximum, but start from several of each of the following before going to the next exposure: 2, 4, 8, 16 seconds, so say 10 exposures of each period, then look at these carefully and decide which look more pleasing.
As a rule it's 500 divided by the focal length of the lens in mm. So 500/28 = ~ 18 seconds. Some people use 400, others 300; the number for you will be determined by your trial.
Take care of the noise/ISO level; just because the camera has 32000 ISO in Manual Mode does not mean the image will look acceptable; you should experiment. I recommend starting at 320 or 400 ISO for your camera, but the optimum value ultimately depends on your light pollution, post processing and exposure time. It seems like the maximum is 1600 or 3200 ISO but for these you really need dark skies and optimal processing (by an expert :).
Needless to say you absolutely must shoot in Raw mode (Raw, 16 MP, 4000 x 4000) don’t even think of only jpeg (long story, all true, don't start me :).
If you don't have a Raw file processor, send me a few images, I'll return with workflow explanation, and there are several free programs that are excellent, in results, but may be a bit involved to use. More on these later.
There is also noise reduction that can be performed, all easy, but the best thing is to make any kind of start, and we'll all look forward to seeing the results.
If you can afford it you should seriously look at getting the Omegon Mount Mini Track LX2 (~£170) as then you can stack multiple images and get results you'll want to mount on a wall. I use one, remarkably accurate, all the more so with 28mm, and you won't need to reposition it for the whole hour. Has good green credentials too.
Whilst this allows longer exposure time, in your case that probably won't be necessary, but it'll pay dividends with reducing noise, well worth doing when you see the results.
Remember not to be disappointed with any initial result as lots of things can be done to guide you along the way.
Regards, William
drja...@aol.com
May 7, 2024, 3:32:55 AMMay 7
to croydo...@googlegroups.com
Hi Adhi
These thoughts assume you will be using just your 28mm lens. This and your large camera sensor will give an extensive field of view. This is good as it makes accurate pointing far less of a chore, and focusing less critical for what will display as small stars even if you are a little out.
However, exposure time will be limited by your static tripod. This is needed to avoid stars trailing noticeably. The longer the exposure the worse the trailing.
The 500 rule with your APS - C sensor and 28mm lens suggests a max exposure of 500/(1.6 x 28mm) = 11 seconds.
This is not long in astro photography terms, but within this limit you should still be able to get good results for typical images at 28mm and a static tripod eg major constellations, eg Orion; star trails around Polaris; interesting night landscapes under the starry sky, the Milky Way, comets, and if you ever go away to arctic regions, the Northern Lights.
This type of astro photography emphasises creativity and originality through interesting and unusual composition, rather than aiming for Hubble type images.
This link to the AstroBin astro imaging archive website shows what types of image can be achieved using a 28mm lens, though some still require a tracking mount. But give it a go and see what you can do. Be prepared for some frustration, as with all astro imaging, but keep going.
|
Using the full aperture, f2.8, will maximise light collection, but it may introduce darkening of the corners of the image, vignetting, possibly also with some elongation of corner stars due to the optics. Stopping down, using a higher f number, reduces these problems but it also reduces aperture, light gathering and makes images noisier for a given exposure, with more grain. F2.8 compared to f2 will very probably be fine.
Experiment. Techniques are available which will help with vignetting in due course but start as simply as possible without them. Start simple.
Now a heresy. IMHO, don't be shy of jpgs. Keep it simple at first. They allow less flexibility in processing but the camera manufacturers put a huge effort into the internal camera processing that creates them. Most cameras will record and save an image in both RAW and jpg. You can come back to process the RAW data later on when you are ready to face the steep learning curve of processing.
It is important though to take several frames of the same field of view. This will improve the image by gathering more signal, the image contents you want, relative to noise. There are several free and quite easy options for this ("stacking") once you have taken the images, which will automatically take account of the small changes in the captured field of view with a static tripod. Deep Sky Stacker works well but you need a computer. You don't need anything especially high powered.
Though not essential, once you've some experience under your belt, it will make things much easier if you use some astroimaging software to set up and control the camera for imaging. This will automate taking several series of many frame sequences, including with different exposures and ISO, help you frame the view and achieve best focus manually, a delicate thing to do manually with a lens. It will also help organise the images, which in the heights of enthusiasm at night can result in an unfathomable chaos the next day, when you come to review or process the images.
I can recommend the 'Backyard' software specifically designed for dslrs, as being reliable, working very well and not too expensive. The Nikon Backyard version has a free 30 day trial and but is not free - I think $50 for the premium full featured version. Check it handles your camera - the software is usually kept up to date though. I have no financial or other interest in the product.
As to where to image, you want the least light pollution and preferably unobstructed views down to the horizon.
Enjoy experimenting and good luck.
James
On 5 May 2024, at 19:54, adhi M <adhi2...@gmail.com> wrote:
Hi all,I'm very new to astro photography but very interested. I have a sony mirrorless a6400 camera with Vivitar 28mm F2 lens and a tripod. Can you suggest1. Easy targets for a beginner like me
2. Places in and around london to capture
3. Low budget equipment to get started with, if anyBasically, Requesting some guidance to get started as beginner.Thank you!
--
You received this message because you are subscribed to the Google Groups "croydonastro" group.
To unsubscribe from this group and stop receiving emails from it, send an email to croydonastro...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/croydonastro/5c24d783-0df4-4f31-9f56-c894f7c08b24n%40googlegroups.com.
adhi M
May 7, 2024, 6:22:29 AMMay 7
to croydonastro
Hi all,
Thank you for the advice, those were really helpful. With all that in mind, I'll get started first, try a few shots and share my progress here.
Thank you again.
Regards,
Adhi
Robert Chandler
May 7, 2024, 6:26:06 AMMay 7
to croydo...@googlegroups.com
I would also consider getting an app with VR capability to help you plan. For milky way photography I use PhotoPills. There is plenty of you tube videos showing how to use the app.
Bob
Sent from
Outlook for Android
From: croydo...@googlegroups.com <croydo...@googlegroups.com> on behalf of adhi M <adhi2...@gmail.com>
Sent: Tuesday, May 7, 2024 11:22:29 AM
To: croydonastro <croydo...@googlegroups.com>
Subject: Re: [croydonastro - 7805] Need advice
Sent: Tuesday, May 7, 2024 11:22:29 AM
To: croydonastro <croydo...@googlegroups.com>
Subject: Re: [croydonastro - 7805] Need advice
--
You received this message because you are subscribed to the Google Groups "croydonastro" group.
To unsubscribe from this group and stop receiving emails from it, send an email to croydonastro...@googlegroups.com.
To unsubscribe from this group and stop receiving emails from it, send an email to croydonastro...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/croydonastro/6e874777-1946-4d97-991b-2450052b09bdn%40googlegroups.com.
William Bottaci
May 8, 2024, 10:43:43 AMMay 8
to croydo...@googlegroups.com
Hello again
Besides the forum reader this is also addressed to the replies; I won't specifically mention the names as it's awkward, easily picked up from the context anyway.
I recall PhotoPills being mentioned quite a while ago; I use it also for my general photography; thanks for mentioning this most useful app.
Advice contains additions and inevitably opinions, all of which add to the whole. I say 'Viva le Difference', and the readers' judgement will of course be in play.
The extent of star trailing is primarily a function of focal length, secondary of sensor pixel size - some use the term 'pixel-pitch' - and then there is our good ol' atmosphere. Without atmosphere and with impossibly perfect optics, star trailing will be more of a problem. The perfect star image would be extremely, microscopically small, but of course the camera records the whole pixel lit up anyway. When it trails into the next pixel the resulting image will no longer be round, but realistic optics and our atmosphere come to the rescue. Apart from possibly the faintest star most are going to intrude to pixels in the immediate neighbourhood, so the shape will be more of a short sausage than a thin line, so realistically less of an issue. Bright stars the more so, they occupy many pixels.
As a guide, four years ago in New Addington, imaging a comet with similar equipment (20MP APS-C sensor) I used 35mm at f/4 (down from f/2.8) 4 secs at ISO 400, and there was no discernible trailing. The fainter stars were between mag 8.5 towards 9. Just fixed tripod. At the time in late July the sky wasn't even dark.
The 500 rule was when pixels were fewer (or is that lesser?) so really 400, even 300 may be more realistic today. Then if the night has unsteady seeing, well you get larger stars; not what you want but it's more forgiving. This is why I say, from the beginning use a series of exposure times. It's not just about trailing; you might prefer the combination of number of stars to their brightness etc.
Stars move slower away from the celestial equator, which in this country means higher up and towards the north.
I should have said, thank you for mentioning it James, stop the lens down a stop or two. Under good daylight conditions, with a less than perfect lens, you get a sharper image, but for stars, depends also on the 'seeing', that is turbulence. How much are the stars twinkling?
Also the paragraph on vignetting, very good; do read again. Even basic software can fix vignetting so not much of an issue, you just lose the fainter stars, but hardly noticeable. If you like, experiment with aperture as well and you'll likely see the difference. Use your experience as well, we just give you a head start.
On jpgs, I did mean to record in raw in addition to jpg, you can always revisit past images to improve on them later. Anyway, all raw images have a jpg embedded in them (whether you like it or not :), it's what you see in the preview and when you're editing etc. You can use the jpgs to gauge the various settings as they're plenty for that. Once and if you process the raw images you can dispose of the 'taken' jpgs to save space, as you can always get them from the Raws.
Now here's something that is extra detail to this thread, related, but I'll mention here even if as an aside; I hope an interesting one:
----
Jpgs contain up to 17 million colours (hues, tones, shades...). Sounds a lot but as we see towards 12 million then not so much. If we do nothing then that's plenty; of course jpgs need all the colours we can see, and because of computers using electricity we have a few more. When I say a few, I mean about 50%.
The trouble comes when we start to edit the image, as most processing discards colours left and right, and it takes very little to fall below what we can see. If photographing children's toys it's not much of an issue; if people with skin tones, blue sky, that sort of thing it'll definitely be noticed.
In particular, when 'stretching the histogram' one is discarding plenty.
Just open up the Levels tool when editing a jpg, not to use but to see.
And it's not just colours we see directly, which is becoming involved (i.e. not here).
----
You camera has an interval timer; this is a most useful feature for you.
You're going to be pleased with your first results no matter how they come out. Subsequent ones will be better, so patience will be a virtue.
Thanks to all (and don't forget to share).
William
Besides the forum reader this is also addressed to the replies; I won't specifically mention the names as it's awkward, easily picked up from the context anyway.
I recall PhotoPills being mentioned quite a while ago; I use it also for my general photography; thanks for mentioning this most useful app.
Advice contains additions and inevitably opinions, all of which add to the whole. I say 'Viva le Difference', and the readers' judgement will of course be in play.
The extent of star trailing is primarily a function of focal length, secondary of sensor pixel size - some use the term 'pixel-pitch' - and then there is our good ol' atmosphere. Without atmosphere and with impossibly perfect optics, star trailing will be more of a problem. The perfect star image would be extremely, microscopically small, but of course the camera records the whole pixel lit up anyway. When it trails into the next pixel the resulting image will no longer be round, but realistic optics and our atmosphere come to the rescue. Apart from possibly the faintest star most are going to intrude to pixels in the immediate neighbourhood, so the shape will be more of a short sausage than a thin line, so realistically less of an issue. Bright stars the more so, they occupy many pixels.
As a guide, four years ago in New Addington, imaging a comet with similar equipment (20MP APS-C sensor) I used 35mm at f/4 (down from f/2.8) 4 secs at ISO 400, and there was no discernible trailing. The fainter stars were between mag 8.5 towards 9. Just fixed tripod. At the time in late July the sky wasn't even dark.
The 500 rule was when pixels were fewer (or is that lesser?) so really 400, even 300 may be more realistic today. Then if the night has unsteady seeing, well you get larger stars; not what you want but it's more forgiving. This is why I say, from the beginning use a series of exposure times. It's not just about trailing; you might prefer the combination of number of stars to their brightness etc.
Stars move slower away from the celestial equator, which in this country means higher up and towards the north.
I should have said, thank you for mentioning it James, stop the lens down a stop or two. Under good daylight conditions, with a less than perfect lens, you get a sharper image, but for stars, depends also on the 'seeing', that is turbulence. How much are the stars twinkling?
Also the paragraph on vignetting, very good; do read again. Even basic software can fix vignetting so not much of an issue, you just lose the fainter stars, but hardly noticeable. If you like, experiment with aperture as well and you'll likely see the difference. Use your experience as well, we just give you a head start.
On jpgs, I did mean to record in raw in addition to jpg, you can always revisit past images to improve on them later. Anyway, all raw images have a jpg embedded in them (whether you like it or not :), it's what you see in the preview and when you're editing etc. You can use the jpgs to gauge the various settings as they're plenty for that. Once and if you process the raw images you can dispose of the 'taken' jpgs to save space, as you can always get them from the Raws.
Now here's something that is extra detail to this thread, related, but I'll mention here even if as an aside; I hope an interesting one:
----
Jpgs contain up to 17 million colours (hues, tones, shades...). Sounds a lot but as we see towards 12 million then not so much. If we do nothing then that's plenty; of course jpgs need all the colours we can see, and because of computers using electricity we have a few more. When I say a few, I mean about 50%.
The trouble comes when we start to edit the image, as most processing discards colours left and right, and it takes very little to fall below what we can see. If photographing children's toys it's not much of an issue; if people with skin tones, blue sky, that sort of thing it'll definitely be noticed.
In particular, when 'stretching the histogram' one is discarding plenty.
Just open up the Levels tool when editing a jpg, not to use but to see.
And it's not just colours we see directly, which is becoming involved (i.e. not here).
----
You camera has an interval timer; this is a most useful feature for you.
You're going to be pleased with your first results no matter how they come out. Subsequent ones will be better, so patience will be a virtue.
Thanks to all (and don't forget to share).
William
On Tue, 7 May 2024 at 11:26, Robert Chandler <rob...@appendixb.co.uk> wrote:
I would also consider getting an app with VR capability to help you plan. For milky way photography I use PhotoPills. There is plenty of you tube videos showing how to use the app.
Bob
Thank you for the advice, those were really helpful. With all that in mind, I'll get started first, try a few shots and share my progress here.
Thank you again.
Regards,
Adhi
Thank you again.
Regards,
Adhi
2024-05-06
Reply all
Reply to author
Forward
0 new messages