Siril ~ astro images update.

Working around some of the issues with image stacking, especially with Siril and Deep Sky Stacker.

Recently I’ve had a number of people comment that they have experienced issues in regards to stacking astro images. Mostly this is using Siril, but the same is true for those using Deep Sky Stacker. I’ve also heard that folks using Sequator have had similar issues.

After stacking the images in one of the above astro image stacking packages, the file is either exported or saved as a tiff or in some cases a PNG file. Typically these files show almost nothing after stacking, maybe just a few stars. Fear not your image is there just waiting for you to draw it out of its hiding place.

To do this you need an image editor that can work with levels and show a histogram. Photoshop, Gimp and others can be used for this. As I’m on a Linux system my tool of choice is Gimp, very similar to Photoshop and a software package I’m starting to use a lot more for astro image post processing. Some of the PP work can also be done in Raw Thereapee but its a lot less flexible compared to PS or Gimp.

48 image stack, unprocessed.
Click to see a full sized version.

You may have heard the term before, but you need to “Stretch” your astro images in post processing to get the most out of them. Below are three images of a stacked photo of the Scorpio/Sagittarius Star cloud area of the night sky. Parts of Scorpio including M6 & M7 is visible along with some of the Nebulae in Sagittarius. The image is comprised of 48 frames of 3 second duration taken at 18 mm – f3.5 and ISO 3200. Total capture is 2.4 minutes. And the image is a failure.

Second edit showing results from image stretch & area to be cropped.

When you look at the processed images you will see what I mean. Either I had a couple of frames that were star-trailed or theres some sort of stacking error, possibly I had something set wrong. I will need to investigate further. The image does however suit our purpose for this demonstration. By shifting the black levels as well as the mid and high points using the sliders in Gimp ( this is found in the colours menu under the heading levels ) the information in the image was able to be brought out.

In the second image you can see a dark band across the bottom of the image, this is caused by the stacking overlap of the horizon at the bottom of the image. I processed this image as a black & white only. I’ve found that some of the Canon Raw files dont convert well in Siril and I have taken to converting them to Tiff files prior to processing and stacking the images. If however I want a single channel B&W image I process directly from the RAW files. I have no idea why Siril does this but the colour images have a much higher success rate after stacking if converted first. This may just be a quirk from within the Linux OS. Currently I’m running Kubuntu 20.04. As time permits I will investigate further.

In the final edited version I have stretched the image both in the shadow levels end as well as mid and highlights. The end result I was aiming for was a high contrast black & white image with an inky black background, very much along the lines of images published during the 1950’s and 1960’s and featured in many books on astronomy and our universe. Had there not been frames or a fault suggesting star trailed images the end result would have been exactly what I wanted, considering the focus and image detail was very good, especially considering it was Canon’s basic STM kit lens.

This shows what would have been the finished image had it not been flawed.

To see how to do image stretching and using very basic imaging equipment check out Nico Carvers – YouTube channel Nebula Photos. I’ve been a subscriber of Nico’s for a couple of years now and he has some of the best tutorials around for astro image processing. Be warned these are long videos, some over 2 hours.

The final link below is to a tutorial Nico has done using nothing more than camera, lens and tripod, exactly the same way as I have done the images above. For those who already have a handle on how to set up your camera for astro imaging these tutorials have well defined points to click on in the progress bar or you can scroll down to the info Nico provides when your click on the show more button in the video description. Note there are other parts to this tutorial for users with Photoshop or Gimp or Pixinsight. Its well worth subscribing to his channel if you are interested in astrophotography.



Reflections & Resolutions & a New Year

Going forward into 2021 I’ve decided that making grand new years resolutions is a waste of time, for me at least. If 2020 has taught me anything its that the best laid plans can be screwed up at a moments notice. I’d wager that there wasn’t a single person going into 2020 that thought that the year would change so dramatically and drastically, or that we would spend weeks & months enduring lock downs.

It certainly wasnt on my radar.

My forward planning consisted of collecting some good images and looking at replacing my current camera gear with something a little more updated, preferably well in advance of my impending retirement.

Unfortunately I had to settle for a good used Canon 700D setup, and while there was absolutley nothing wrong with the 700D I never really got along with it. It did help my decide that I prefer the all in one solution that the top end bridge cameras provide, and while there are compromises with this type of camera, they arent sufficiently large enough to really be as big a drawback as one may think.

In regards to 2021 and “Akiwiretrospective”, I have for some time been considering whether to continue the blog and if so in what form. For now at least it will continue as it has been. I want to watch where the camera manufacturers go with new technologies and upcoming releases.

I have watched the trend to full frame mirrorless systems from most of the major industry players as well as the demise of Olympus, with no small amount of alarm. While the Full Frame trend may be music to the ears of some within the Pro Photography world and the upmarket enthusiast ranks, given the pricing structure being employed, for most of us on a average budget these cameras are well outside the expenditure level of the average hobbyist.

Take for example the new Canon RP plus the 24-240 mm lens, being sold as a kit. At $3795.00 NZD a pricey bit of kit, or the EOS R body only at $3480.00. The pricing is even worse when it comes to the R5 & R6. Nikons Z5 & Z6 while somewhat better placed pricewise still set the owner back a serious amount of funds. Not as hefty as their Canon counter parts to be sure but just how many of the enthusiast/hobby owners actually need a full frame camera?

Panasonic’s S series full frame mirrorless cameras are in the same price echelon and also need a substansial investment.

At present the major camera makers are still producting lower tier cameras, with the likes of Canons rebel series DSLR’s and the 90D range. Its getting to the point where these differing crop sensors cameras are likely to morph into one main offering and a low specced budget line as an entry level point.

Fujifilm is not immune to the high priced market either with their XT3 & XT4 range of cameras being stratopherically priced and in some instances (depending upon the kit offered ) match or exceed the cost of some Full Frame camera offerings.

In Fuji’s favour they actually have a range of lower tiered products to encompass just about any need, From the XA line, the X-T 100/200, the XE line or the XT 20/30 as well as Xpro theres something for just about everyone. In the new camera sector Fuji still has one of the best quality camera lineups out there. Staying with the crop sensor system has been (IMHO) a very smart move. Given the huge print size available from the likes of the XT4 for pro level use, if you need anything bigger then the GFX medium format range is the next step. A huge step in price too but for a good many Pro Photographers I have no doubt 50 or 100 megapixel medium format cameras are a big attraction, especially if huge print sizes are needed.

I see little to suggest that Olympus will continue in its current product lineup for much longer now that the company has been sold, and Pentax still seem on the verge of oblivion, which I personally would hate to see as I’m a long time fan & user of the Pentax brand.

We are going to see the traditional camera market continue to shrink as the smartphone becomes even more adept at photographic work, as well as producing excellent video quality, providing you dont need a large zoom range. However the telephoto aspect of some of the top tier smartphones is becoming increasingly better as technology is developed to improve this function while allowing for improved image quality. It would no longer be smart to ignore the smartphone world as a good many users are finding that they are getting excellent results without having to tote around a bag of heavy camera gear.

For my wife and myself going forward we will be looking at purchasing a gimbal for our smartphones for both photographic & video work, and I’m almost certain that the Sony RX10 IV will be my next camera for general purpose photography. It brings in one package 95% of all the things I need from a camera. As for the powerzoom rather than manual zoom lens – I will no doubt learn to adapt and adjust my shooting technique. We will just have to see what the new year brings. Until then,

Happy Snappin’

The Future for Akiwiretrospective.

Its been a while since I last posted anything, I’ve been rather busy with other things, mostly work. Its meant very little time behind the camera unfortunately.

This trend is going to continue for a while yet as we run up to the Xmas break. I’m intending to take almost a month off for a well earned break this year. It will be the first time I’ve had a continuous break of this duration in over fifteen years, around the time I started the “retrospective” blog on the BlogSpot platform.

Over that time the blog has expanded a good deal past what I had originally set out to achieve, and looking back I can say that it has been a worthwhile labour of love.

I recently sold all my Canon gear as well as the majority of my Pentax film camera gear as well. No I’m not giving up photography entirely, but I am reassessing what I want to get from it.

At present I have a good smartphone for everyday snaps, something I would not have even entertained 10 years ago, but progress in the mobile camera world has taken huge steps in making the smartphone an invaluable tool for many hobby photographers and no doubt for many serious photographers as well.

I still have my trusty Fujifilm HS20 EXR bridgecamera and one film camera so I still have the means to get a few good images when they present themselves.

Over the past few months including lockdowns I’ve been considering the tools that I use for my photographic endeavours, and I’ve come to the conclusion that the bridgecamera is the best suited to my style of photography. This is especially important going forward, as in a little over six months I retire and have to make the decision to either continue working or have a reduced income. If the latter then a bridgecamera is the tool of choice, there is not likely to be room in the budget to swap lenses or buy others to fulfil a need.

Similarly I am considering continuing this blog in its current form or switching to something a little different, although its not immediately clear as to what that might be. Certainly not Twitter or Instagram, two platforms that are far too chaotic to be of any real use in this endeavour. A dedicated Facebook page is one consideration.

I am open to suggestion from our readership, so if you have an idea, leave a comment.

Thats it for now, I will continue posting the odd photo when I have the chance. In the mean time I hope you all manage to have a relaxed and enjoyable Xmas break, pandemic or no. As always

Happy Snappin’

Taken with Oppo A5 in Panorama mode. Massive streaming cirrus cloud fanning out above Mt. Kakapuke

A day at the mill.

Saturday 10th October saw a number of our members from the Te Awamutu Camera Club venture forth for a trip to Endeans Mill. The mill lies approximately one and a half hours drive from where I live, so not too long a trip although there were times when the GPS in my phone wasn’t sure exactly where I was or where I was going. Nonetheless I arrived on time and in good company.

We preceded to wander around the property which covers a considerable area. The mill is curated as a living museum and as such has been left in a “as it was” state. The image of the memorial stone tells some of the story.

I used the Canon 700D with the 18-55 STM & 55-250 STM standard lenses and shot in aperture priority. I found that P Mode wasn’t giving correct aperture settings for some of the shots, resulting in a number of blown out images.

Getting the images onto the computer I processed all of the following images using Photoscape 3.7, combining different film simulations, filters and some vignette to process these images as they may have looked if they had been left in various places at the mill over the years. Think 1930’s through 1970’s film colorings and processing and how time may have changed the printed images.

After our mill visit we moved further along the road to Blackfern Lodge. A great place to visit and have lunch and wander around with a camera, its a place I will need to come back to as is the mill. There’s simply too much to see to take it all in in a single visit. Below are two images taken with the 700D at the Lodge grounds.

The 700D wasn’t the only camera I had on the day. I was also carrying my Pentax MZ30 with a Tamron 18-300 mm lens attached. Unfortunately the MZ30 developed a problem with the communication between camera and lens and I was only able to take 9 shots. On returning home I put the standard 28-90 Pentax lens on it and the camera works fine. It would seem the earlier generation Pentax didnt like the Tamron. The lens does however work fine with my Pentax MZ6 so thats where that lens will stay.

As a backup to the two main camera I had my Oppo A5 with me for the wider shots I was looking to get. The images are less intensely edited as the files from the phone dont standup too well if cropped or over edited. They do however serve to show just how handy a good smartphone is when wide angles are needed and you dont over process.

This video clip shows the mill and what it looks like if you were to visit today.

Video By: Silverline Pictures (NZ) on YouTube.

Imaging the Winter night sky

Really clear nights with stable atmosphere have been few and far between of late. Add to that the winter rarely grants us too many nights at best and it makes a recent Saturday night a rare event.

With the Southern Cross, Coal Sack, and Eta Carina all very low in the night sky it was a pleasant surprise to see stars right down to the horizon and still maintain clarity. Overhead Scorpio & Sagittarius are passing through the zenith and with Jupiter directly overhead saw me shooting a series of RAW & Jpeg images.

I’ve been slowly processing the images over the past week using a variety of tools. Namely, DeepSky Stacker, Sequator, Siril for image stacking with RawTherapee, Lightroom (trial version), Gimp and Photoscape for various parts of the image editing process. Not being well versed using Gimp produced quite the learning curve, but as I use this application more frequently I’m beginning to come to grips with it. Long time photoshop users will no doubt find Gimp very familiar.

The reason for the amount of differing image tools varies on what the end result  is expected to be. Processing the RAW files takes a different set of tools to get the most from the images and the same can be said for  processing of the Jpegs. I find that some tools are better for each of the different filetypes. There are those who will use the same tools no matter what they are processing and that is fine as well. Using free image processing tools is what we are concentrating on in this series of images and is in keeping with the Frugal Photographer ethos.

If you have access to the paid packages and you are comfortable paying  what in my view is some pretty hefty pricing then go for it, there is no right or wrong method, merely what suits your desired outcome and affordability criteria.

25 x 10 sec f4 @ ISO 1600 Jpeg files Stacked in DSS and processed in Raw therapee & Photoscape.

25 x 10 sec f4 @1600 ISO CR2 Raw files Stacked in Siril and processed with Gimp & Photoscape


25 x 10 sec f4 @ ISO 1600. Stacked in Sequator and processed with Gimp & Photoscape.

20 x 10 sec f4 @ ISO 1600 CR2 RAW Files stacked with Siril and processed with Gimp & Photoscape

20 x 10 sec f4 @ ISO 1600 Jpeg Files stacked with Siril and processed with Gimp & Photoscape

One of the most noticeable things when processing these images is just how much data is available in the stacked Jpeg files. The camera does a good job of color correction, distortion correction and overall detail balance in the image. This makes stacking and final processing a good deal faster than processing the RAW files.

I still feel that visually the RAW images are a little more refined but lack the visual impact of the final Jpeg edits. I have no doubt that I could with time and practice match the appearance of the Jpegs if I were to push the RAW file processing somewhat more intensely. However unless you are intending to print these images at A3 or above I have no problem with printing the Jpegs at A4 or A3 without needing to further process the RAW based images.

This is something I noticed markedly with my Fuji XA2 when using it for astrophotography. Stacked Jpeg images from the XA2 were spectacular and lacked nothing for detail, color & contrast. Given how good Fuji Jpeg files are this really comes as no surprise and while RAW files do hold a huge amount of data I suggest you ignore stacked Jpegs at your peril, you may just be missing  an important part of your astrophotography process.

I cannot however say the same when it comes to the images from my 700D. Thats not the cameras fault but rather the 18-55 STM lens while sharp over the center 50% of the lens is woeful around the periphery as can be seen by the elongated star images in the outer portion of the images. Not a good lens for this type of work. It is at best adequate and if you like me haven’t anything better then it does suffice, and in reality I shouldn’t grumble too much.

I only have to step back 30 years to remind myself that I would never have dreamed I could take images such as those above with what is a pretty standard entry level camera and kit lens. We have certainly come a long way in the past few decades.

Happy Snappin’

A visit to a local bird park.

We took the opportunity this morning of visiting  Shaw’s Bird Park.

The park can be found on the southern outskirts of Hamilton and is well worth the time to visit. The public needs to get behind this private venture and help sway the local city council from taking part of this land away for a road to connect a local subdivision.

As always it seems that private individuals have  little recourse in these matters. An online petition has been set up and to date has garnered several thousand signatures, mine included. In the mean time if you have the odd packet of birdseed languishing on a garden shed shelf its likely the Park can  put it to good use.

White Faced Heron

We didnt spend as much time as we would have liked to, we had other places to visit therefore our stay was somewhat shorter than I would have liked, but we will definitely be returning to see some of the other areas we missed today.

Perhaps the highlight of the day was meeting a Tui that has a penchant for licking your fingers. They have an amazingly delicate tongue.

With the advent of Covid-19 and restrictions on movement staying local and supporting our local attractions is a good way to spend some hours.

Apart from the bird life theres a huge array of native trees and flora, and its obvious that spring is on its way with all the new buds and magnolias in flower. This will make a great place to be on a hot summers day with lots of shade and water areas to keep you cool.

All images taken with the Canon 700D and the 55-250 IS STM lens.

Oppo A5 – EOS 700D & Raglan revisited

Being as it was my wife’s birthday this Friday just gone I thought it appropriate that we dined out in style.

Well dine out in rustic style that is. One of our favorite haunts is the “Wharf Fish & Chip Shop”. You may have seen previous articles featuring this place, and its rustic charm and simple seafood fare is what draws a lot of folks back for a return visit. We are no exception. Plus we just like being somewhere close to the sea and the fresh air. Its gives one a chance to chill out and forget about all the problems associated with Covid-19. Fortunately we are only at level 2 status and are pretty much free to go where we want so long as we observe a little social distancing and are mindful of hygiene.

It was also a really good reason to try out the camera in my new Oppp A5 smartphone. Its no camera giant compared to flagship models like my wife’s Note9 with only a 12 mega pixel main camera. However in good light it seems to acquit itself quite well. Some of the images I took with it have been printed on 5 x 7 glossy photo-paper and it is unlikely you could tell from what camera the image was taken. In fact when put alongside images shot with the 700D, I doubt that anyone is likely to tell the difference at this size and it is precisely the same even on A4 prints.


I have to say that I’m impressed with how the phone dealt with this scene given that the harsh light outside of the seating area and large dynamic range. A good many cameras fail in this situation, including the 700D, which struggled a little in this instance. In this particular instance the relatively slow aperture of the 18-55 kit lens just wasn’t really up to the task and it shows. The much faster f1.8 lens of the phone’s camera proved to be better at balancing the light values, and of course theres some fairly serious computational work going on as well. None the less it does show an area where the DSLR with standard lenses struggles to compete. Its this very reason that sees me almost exclusively have the EF-S 55-250 mounted on the 700D and I use the smartphone for closeup, wide field work or where I want a more panoramic view.

For the more traditional landscape image I would move back to the DSLR and wide lens & telephoto when needed.

Having said that I’m not displeased with the sharpness and tonality of this image. I didnt have to do much apart from a vignette and a small crop to give the image the ambient look much as I saw it when taking the photo.

I’m having to work a good deal harder to get images I’m satisfied with the 700D. The sensor is the same as the 650D apparently, and that was a nice sensor. Where the difference lies is in the Digic 5 processor, it handles the light substantially differently to what I had become used to with the 650D and the 1000D, and is taking quite some sorting to get used to it. Frustratingly this has meant that the keeper rate has dropped off.

Another quirk of this camera is in live view, which is considerably better than the 650D. Unfortunately unlike mirrorless cameras you cant sufficiently reduce the focus area as in a good mirrorless camera, hence you get missed focus on a number of shots. The image below is a classic example of this.

I wanted the focus to be on the closet of the posts and throw everything beyond out of focus. I new it would look quite nice compositionally with the couple just coming into shot in the background. The image had good depth of view whilst holding all but the foreground object in focus. In the live view screen it appeared that I had the focus point spot on. Unfortunately quite a lot of the mid ground became the point of focus with everything forward of that out of focus. I was using the 55-250 so was hoping for good smooth out of focus areas. That wasn’t to be.

Suffice to say at this point the 700D is proving to be quite the challenge. I’m just stubborn enough to keep at it until I strike a setup that works the way I want it to. I will update my progress as time and conditions permit. Until then:

Happy Snappin’

More from the Canon EF-S 55 – 250 mm STM lens.

The more I use this lens the more I’m coming to understand some of its quirks. Its not really a low light shooter, I found that out quite quickly. In fact the Canon ef-s 55-250 MkII IS lens was better in low light due to it being half a stop faster at f3.5 Vs f4 of the STM version. Half a stop doesn’t seem that much but its surprising how much brighter the older lens appears to be, at least in tests shots I’ve done with both lenses.

The STM version beats the older lens hands down in the AF stakes. Its ability to lock on to a subject with minimal to no focus hunting is so much nicer to use. The images of the bees had it working pretty hard, and while it did miss focus on some shots its hugely more reliable than its predecessor.

I’ve mentioned previously that I thought the 700D seemed to be a little soft in focus, but after the last couple of days in good light it seems to be pretty well spot on. Images appear relatively sharp for what is a kit lens, and at this price point I wont be complaining. I will however say that the Fuji XC 50-230 mm is noticeably sharper, but doesn’t focus as fast or quite as accurately as the Canon lens. Having said that I’m aware the the Fuji XC 50-230 lens performs considerably better when paired with an XT-20 or better Fuji body.

For the time being however, and until I win the lottery I will stay with the Canon 700D for the short term, although the call of the Fuji is strong 🙂

Taking advantage of a crisp frosty morning I opened the lounge window to take a shot of the vista seen below.

Shot at 55 mm focal length.

As you can see in the image the frost had just burnt off but the fog banks were still rolling through the valleys. This view was far more spectacular a few years ago before the oak trees in the foreground started to encroach on the view.

Shot @ 135 mm

The image above is taken with the 55-250 and the focal length is 135mm. I deliberately did this to give a sense of scale when compared to the previous image shot at 55 mm.

The above image is shot in vertical aspect at 250 mm, and post processed in Photoscape 3.7. The central tree seen in all three of these images is approximately 1.5 kilometres away from our house. I’m pleased with the amount of detail and resolution afforded by this lens at this distance. It shows good colour in the image as well although I have pushed the saturation a little to better the sky colour.

Okay so thats the wide to telephoto range for landscape and distance shots. Colour and detail is good, no complaints thus far.

What about using the lens for closeups?

As it turns out, not too shabby there as well. Long time readers will know that I have a love hate relationship with bees, not because they can sting but because they are not to easy to shoot and get a reasonable/good result. The low level sun we have to work with in winter can make this task just that much harder, creating deep shadows and very bright highlights. Add to that the little critters dont stay still for long makes the task harder. The AF on this lens is so much quicker than the mark II lens in this regard. Anything I pointed it at was locked onto with minimum of fuss.

Today the bees were working on tiny blue flowers, and I mean tiny. They arent any bigger than five or six millimetres in size, just enough room for a bees tongue. These are attached to a myriad of stems and small leaves which makes for a very busy background, making it hard to separate the bee from the plant. To obtain that sort of subject isolation generally means using a very fast short focal length prime, meaning mega bucks for a fast lens.

So how did the big kit zoom fair at subject isolation and resolution? You be the judge, but personally I think it did a pretty good job for a telephoto lens. Bear in mind also that these arent shot as macros but rather getting as close to the subject as I could and using, in some cases, the full focal length to zoom in and get the shot. And before you ask, no you cant do this with manual focus, the bees just move too fast and thats where fast reliable AF wins out.

My favourite model doing a spot of cleaning, Shot at 250 mm from approx 80 cm distance.

Actually you can do this with manual focus, but you need to be setup on a tripod and have selected one area and pre-focused for that area. I would also use a remote shutter app or as in my case ( pre WiFi camera) a remote wired shutter release. Tedious but it can be done as macro photography specialists have shown. I’m not that dedicated a macro photographer, well not yet anyways.

Below are three images all shot with the 55-250. For larger images click on any of the images in this post and you can see them full size on my Google Photos listings.

Shot @ 200 mm
Shot @ 250 mm
Shot @ 250 mm

In conclusion:

To date I’m well pleased that a $400.00 lens (thats the new price here in NZ) can provide a good deal of sharpness, contrast and colour with a very usable focal length. To better the overall performance of this lens would require spending in the order of two to eight times the price and you still wont get the focal length. If you were thinking of getting this lens to add to your kit, go for it you wont be disappointed. Just take some time to learn how it behaves and when to use it.

Camera settings were as follows:

  • Mode: P Mode
  • AF: Single shot
  • Metering: Spot
  • Photo-style: Standard, setup to mimic Fuji Velvia.
  • ISO : 800
  • Continuous shooting: Multi-shot
  • Ev: +1/2 stop

With the camera set in P Mode and the ISO set at 800 I was able to adjust aperture or shutter speed with the command dial depending on the result I wanted. As the camera generally chose f9.5 for most of the images I didnt have to do much other than consider composition or wait for the bee to move into frame for a image worth keeping. The beauty of P Mode as I have said previously is that it allows on the fly changes with the camera picking either correct shutter speed or aperture depending upon what you desire as an outcome. By and large the camera choose pretty well. It selected either aperture or shutter speed pretty much as I would have done.

This is something Canon cameras do very well and is an often overlooked feature, lost in the inane desire for everyone to shoot manually. Theres a reason camera manufacturers include this mode, and its not necessarily for beginners as most beginners really need a good deal of time to grasp how aperture, shutter and ISO works together. P mode is there for those of us who know what those terms mean but want the flexibility to make rapid adjustments without having to clutter up our thought processes with worrying about settings and get on with the more important task of actually composing the image and taking the shot.

While you are busy trying to decide what aperture or shutter speed you need, I have dialled in what I want, taken the shot and moved on to the next subject or image. So dont be afraid to try it, you may just find its a handy mode to use.

As always

Happy Snappin’