DSLR colour balance...get it right.

[Peter Ward]

Houghy,

While it was on special the ST4000 was a pretty good buy. I can mention all the reasons why I still think this is so, but this is *totally* going off my original post..... I'd be happy to discuss that elsewhere.

The Tarantula nebula is not inherently blue or cyan. Unless you failed the Ishihara test, it would look red if you retina had cones that worked in the dark.

The fix, and I'm not talking about photometrically/pantone accurate dead nuts on colour, just a "shade" or two fix, is to simply use, well Iris, like Scott pointed out, or PS and simply adjust the red curve.

There is no law that says this is necessary, and sorry to harp on, but I suspect Canon would have a problem pedaling happy snap cameras that made skin-tones look green (unless Marvin the Martian is your best buddy)

[dugnsuz (Doug)]

I look forward to your posts Peter for the rough n' tumble that follows!!!

I don't want to get into the s@#t fight, but just want to say thanks for the tip regarding playing around with the red channel in the Curves tool.

It's these tips that are so helpful to us novice guys - Thanks

Doug

[rat156]

Hi All,

Here's my tilt on the subject.

I work hard to get an accurate colour balance in my images. I try to get the Ha the right colour, which can be seen, just not from astronomical objects, I try to get stars with colour, I try to get a neutral grey background.

If someone has taken an image which is good except for the colour I'll tell them I think the colour is off, if they care, they'll try and fix it.

I now rarely comment on others images mainly because of the comments like Ken's vitriolic replies that Peter has had to put up with. I believe, at least in this thread that Peter was merely pointing out something that can be fixed easily. Something beginners may not know.

I have some pretty high end gear (none of it purchased from Peter), but I still love some of the first images I took with my DSLR, even then I struggled with colour balance. I'll never say your images are crap because you don't have the right gear unless the person has reached the limitations of their gear and are asking why their images are crap, which sort of shows that they realise what's going on anyway.

Cheers
Stuart

[ballaratdragons (Ken)]

Originally Posted by rat156

I now rarely comment on others images mainly because of the comments like Ken's vitriolic replies that Peter has had to put up with. I believe, at least in this thread that Peter was merely pointing out something that can be fixed easily. Something beginners may not know.

It's not the fact that Peter gave a great tip for a simple colour adjutment. That's fine.

It just carries that implication that if an image isn't the correct colour, it isn't very good.

It's just that it has that 'put-down' feel like some of these samples of other posts by Peter:

"If you want to have a bit of fun and don't take astro imaging seriously, get the EQ5/6" .

"The small sample of EQ6's I've tested ran at about +/- 50 arc sec....and landing on a chip after a 150 degree slew? ...give me a break"


For his 1st quote, does that mean that those of us with EQ5 or 6 are not trying to be serious about our imaging????

For his 2nd quote, I'm not the only one with dead accurate GoTo's on an EQ6.

I slew all over the sky all night and get spot-on GoTo's, and that it with a Toucam which is equivelent to a 6mm EP. That's Damn good accuracy! Give me a break!

Peter, you are probably dead right in all that you say, but sometimes the wording is very discouraging. It has the feeling that you are putting down others attempts.
You may not mean to do this, but it comes across that way.

Some of the replies from others to some of your previous posts should indicate that:

*On the topic of winning awards - if the only way to win an award is to use high end equipment then I would have to question what it is that is being awarded? Unfortunately however, often this may be the case. I think it sends a bad message though to those who may choose to submit images using cheaper equipment. (why even bother if high end equipment always wins?)

*this thread is pointless, if it is going to be a bickering session between the very experienced.

*Not that i mind a good discussion, I feel too that some will be discouraged in submitting there work because it doesn't come up to standard.

*No insult or anything else towards Peter, great images and all that, But how can he even start to compare his images taken with his semi professional gear to the average amateur on this site.

*I will post mine and you post yours let the viewer decide " is in my opinion getting a bit childish. Naturally His images have to be better, otherwise what a waste. The more experienced amateur on this site would love to have Peters equipment, I am sure. But this ‘my images are better then yours’ is ludicrous.

*What really gets me going is the way some people throw around all these obscure theorums that try to prove that they are smarter than the next guy, (see earlier posts), and because of this they must be better astrophotographers.

*IIS is an amateur forum I assume formed to help us newbies (as we all were once) increase our knowledge and if wanted our photographic skills.
I love Peter Wards images and a lot of others peoples too but this forum in itself is not an imaging competition, we look or at least I do, at the pics submitted and relating them to the gear used judge them on that.

*Are Peters images spectacular when compared to his gear? l don't know.
Are EzyStyles images spectacular with his gear? you bet your a**e they are, how do l know? because l can relate to the gear and other images taken with similar gear, and let it not be forgotten these two probably have about a 30 year gap in experience. l use Eric as an example only and could have used many others, hope Eric dosen't mind.
Many of us didn't know a thing about astrophotography 2 years ago and l for one am more than happy with my progress as other are no doubt happy with theirs Ken, Barb & Dave as examples, if those that think their knowledge is superior want to banter amongst themselves fine but do it privately please, this is l think still an amateur forum.

*Well Peter I hope you are wrong on that score. I seriously hope we stop seeing competitions where the winner to every category is an Takahashi 6 inch refractor on a Tak mount.

*As mentioned by others previously it is not too hard to consider the relative merit considering the equipment used. Who would be bothered submitting images while such a view exists unless they own a Takahashi. (sorry about the thread diversion here but I think it is an important point because it is a hobby and even an achromat on an Eq6 is mighty expensive - and many of us are not flush with money to afford the great gear).

*Wasn't the winner of the last David Malin award a picture of comet McNaught through a camera lens? I wonder if it was an apo or an achromatic camera lens? (or indeed if it should matter). If its ok to take images through an achromatic camera lenses why not achromatic telescopes? Another was a picture of the moon in colour - very imaginative. I dont think these won due to the fancy equipment used for the large part.

*I personally think forget the mount and equipment creep, focus on the technical aspects of the imaging and be happy as there is always better equipment (and you can always download HST images if you really want perfection).

As mentioned elsewhere in here and other Forums, text messages can be misconstrued in meaning coz it is hard to replace every emotion with a smilie. So my hope is, Peter, that you are not putting down the efforts of many because of their 'cheap' gear.

[vash (Ashley)]

I Prefer the natural look that the camera puts out with my images, Most of the bright nebula turn out just fine and don't need to much touching up, but some nebula such as the tarantula come out completely blue, at least the times that I have tried it.

I also have spent countless hours trying to figuring out how to do things in photoshop when I get bored, but it's not easy to pull out red when the data captured is blue, thats just the light the camera has collected. This is compounded with the fact that most of the people with unmodded cameras are just starting out and aren't sure how to process images to there full limit. Only by posting their Images and getting positive feed back and helpful info can they learn this art.

I don't mind seeing a posted picture with incorrect colour, because I think to myself, " hey, thats what mine looks like, It's not me then". This helps me pluck up courage to post my images.

With adjusting curves in photoshop, it's not that simple to just boost up the red, this introduces more noise to the image I have found and to takes a long time to get them all balanced out. BUt I haven't found the sweet spot yet, I'm sure there is one though.

[ballaratdragons (Ken)]

But, on the topic point

I do try to get my images to a point where they are hopefully the right colour.

I do this by googling the object in google images, and what pops up?

Heinz soup! 57 varieties!!!! I end up choosing the colours that look most pleasing to me from the vast selection (many by professional astronomers). That also tells me that even professionals can't be decisive about the 'right' colours.

[Luke Bellani]

Hi All,
IMHO which carries very little weight, colours would depend on what my aim is.

I would dare to say that 90% of the beautiful images published from Hubble are enhanced with false colours. and that is usually stated.

If my aim is to bring out subtle detail in nebular images then the use of false colours would IMO enhance the image.

On the other hand, if my aim is to produce a wide field image of Eta Carinae then getting the colour about right would be my aim.

I like seeing images with lots of detail. To me "true" colour is secondary.

But then I'm not a scientist and I don't do astronomy for its scientific value.
I just like to do it my way, get better at it at my own pace and get the most out of the gear that I have.

It will be a long time before my abilities exceed the abilities of my gear. when it does, if ever, then I may or may not upgrade. It will depend on my finances. I can say one thing for sure however. A $6000 camera will never be on my shopping list. It certainly cannot produce images as good as Hubble and I can't afford a one of those either.

When I find myself being influenced by what someone else thinks is acceptable or not in this hobby then it will be time for me to give it away.

Cheers,
Luke.

[Peter Ward]

No implication about it. When someone takes a colour image of NGC2070 using a bog standard DSLR and it looks blue then I don't think it's a very good rendition.

Yet it is so easy to fix, and I mentioned how.

You'd think this was the opening sequence to Life of Brian and I said "Jehovah!"

Saying that's "nice" for the sake of being PC is just like my mum would have said before she put a crayon picture on her fridge.

Originally Posted by ballaratdragons

It's not the fact that Peter gave a great tip for a simple colour adjutment. That's fine.

It just carries that implication that if an image isn't the correct colour, it isn't very good.

.

As for the Ken's tirade...aye carummba....what has that got to do with getting colour accurate? Is there something in the water out there?

[ballaratdragons (Ken)]

Originally Posted by Peter Ward

Saying that's "nice" for the sake of being PC is just like my mum would have said before she put a crayon picture on her fridge.

My Mum honestly did like my Crayon drawings.

She told me so

Originally Posted by Peter Ward

As for the Ken's tirade... Is there something in the water out there?

What is in our water out here depends on the colour of the water

The correct colour being brown

[Peter Ward]

Can't argue with that!

Originally Posted by ballaratdragons

What is in our water out here depends on the colour of the water
The correct colour being brown

[Alchemy (Clive)]

why is it peter that wherever you go a hornets nest is stirred up?
i passed mostly previously, but are you deliberately doing this?

re color balances and images.... i have added a post to one of your images, you will find the coments i have made are factual, although not in the spirit of the forum as a rule, the image was poted by you on the 13th of january called Carina and SAG triplet (its the second image)... i suggest we all have a look closely. My previous comment in this thread was for the other image i passed on the second one out of politeness.

People do this as a hobby for pleasure.... every now and then a tip is given gently to people to help their problems, i personally am happy with the color that i get from my dslr, the nebs turn out pink but so what, thats how my camera sees it, others wash red all over everything , well thats their perogative if they like it, so be it. And what should we ban unmodified DSLRs

if we insisted everyone check their images for a GV2 color balance before they posted.... well id go elsewhere.

i agree with ken on most of his points, something may not be written but thats the message i am recieving too.

[Bassnut (Fred)]

Sheesh Guys, Ive read 1st Peters post a few times, seems clear to me, it was about colour balance not dollars. Sure, dont have to be red, most of my pics arnt (NB), and you can do what you want, but you all know hes right, in RGB Astro, red is prominent, it must be, Hydrogen is everywhere ;-). I like a bit of Argy bargy, stirs the blood, but dont make it personal.

[Hagar (Doug)]

Enough! Enough!

Peter, How do do feel about black and white images(monochrome)? These certainly do not fit the colour correct nature you seem to be expounding. Some of the greatest imagers and photographers only use monochrome imaging devices, usually for their sensitivity. These are also award winning images which are definitly not colour correct.

[Peter Ward]

Love H-Alpha B&W!

This one O.K.?

http://www.atscope.com.au/newsky/ngc2070haf7.jpg

Note shape of edge stars...not too comatose and blobby

Originally Posted by Hagar

Enough! Enough!

Peter, How do do feel about black and white images(monochrome)? T

[Alchemy (Clive)]

No edge stars are ok, but.... around some of the brighter stars there are off centred halos, is this just an optical defect.

[acropolite (Phil)]

If the colour is pleasing to the eye and has impact then it's OK by me.

[Peter Ward]

Nup, I trust the optics. I hear the Vatican will be making Roland the patron Saint of refractors soon.

Probably a reflection off the filter

this one also has the same problem

http://www.atscope.com.au/BRO/images/halphacarina.jpg

....dammed Yankees

Originally Posted by Alchemy

around some of the brighter stars there are off centred halos, is this just an optical defect.

[edwardsdj (Doug)]

To my eye those halos seem to be pointing towards the centre of the frame. Was this imaged with a refractor or RCOS?

[gregbradley]

Hello,

My name is Greg Bradley and this is my first post in this group.
I frequent the Meade Melbourne Group and others but its nice to have
an Aussie forum and its distinctly in your face style.

Here is a link to my images site:

http://tinyurl.com/2fyepd

I can relate to a lot of your posts as I also have not been doing this "that" long - about 3 years now, starting with a Meade LX90 (a lot of fun).

I have done a lot of imaging with DSLRs and have modified quite a few.

Colour balancing with a stock DSLR is a little tricky depending on the model. But stock standard they tend to be baised towards the blue and inhibited in the red.

This is because the chips are sensitive to UV as well as Infrared and the filter in front of the DSLR chip is called a hot mirrored filter and reflects the UV and IR components.

With these removed you increase the red sensitivity many times and the general sensitivity of the camera about 2.5 times.

When processing modified cameras it helps to have a custom white balance which is a shot of a Photographic 18% grey card ( about $20 from a photographic store) taken at midday in sunlight. That handles a lot of the red bias.

The new Canon 40D seems to be a lot more sensitive to the red than any other camera I have seen used and also has a 14 bit converter (Sbig and others use 16 bits ie. 65535 shades of grey, 14 bit is about 1400 or so, 12 bit is 256 so its quite a jump).

I have been thinking about getting a Canon 40D recently as it is such a leap forward for DSLRs. Probably the first major improvement over the venerable 350D.

Balancing colour is a tricky subject and one that I am not particularly expert in as I tend to process my images too saturated in colour and have to show restraint! Some use G2V stars and process until they look white. Most though use the histogram feature in Photoshop that shows the histograms of each colour channel and you can easily see which one is biased and then pull it back using curves or levels. Auto-colour in Photoshop always seems to make images too green to me.

I had to laugh about the post about the Tak 6 inch refractor on a Tak mount winning competitions. Funny, I have one of those and was thinking of upgrading!

Oh well, everyone has their own viewpoint otherwise life would be dull indeed.

Nice to be a newbie on this group.

Greg.

[Bassnut (Fred)]

Welcome Greg, nice to see you here. Tell us about the gear you have, and post some pics .