Are Megapixels a must?

[Mache]

I'm really tempted to shell out for a new Camera next month for a prime reason of more megapixels (12 to 20) but i really want to know 'Are Megapixels A Must'?

I took this a couple nights ago which i really impressed myself, but i keep thinking to myself if only i had more MP's to it i would have the same job but a better image... wouldn't you agree??

(Plus Jpeg files really don't do this image justice)

Cheers

Mache

[hobsey]

I have always been told that megapixals are only a must if you intend to print them off on anything larger than A4.

[Mache]

I always thought it would bring more clarity cleaner image to be honest, but usually stacking images i thought it bettered the image more, but having said that i wouldn't need to take 100 shots instead i would only take 50 because of the doubled Megapixels?

[ronin]

Is the DSLR on the 4SE or the Tamron ?

As pixel size is generally matched to focal length it makes a difference.

Looked round the internet at this a day or two back and whatever site (SBIG I think) did say a pixel should be 1 to 2 arcseconds, giving finally an general values of 1 pixel = 1 arcsecond.

This was given as a ballpark figure and it stuck simply owing to the 1:1 nature of the values.

So on the Tamron more (smaller) pixels would appear to help, on the 4SE no apparent improvement.

Rather hope an imager will come along and supply more information/values.

[Mache]

DSLR on the Tamron 18mm @ f3.5. Just tried to Google a Arc Second and still didn't understand it sorry.

[ronin]

I don't much either.

I was reading a few post on SGL about 4 weeks back and people wre saying you need to match the camera pixel size to the scope, I thought it was the f number but seems I got that wrong.

I turned up the SBIG site and they had a guide, or at least an explanation.

As best I recall their explanation came to:

You should aim for 1 pixel to match to 1 to 2 arc seconds as produced by the lens focal length.

Think they said if good seeing then you can go for less as in 0.6 pixel.

If poor then bigger.

Ballpark idea was a pixel should come to 1 arc second.

On the 4SE at 1325mm FL that means a pixel size of 6.5 micron

On the Tamron at 200 (say) that is 1 micron

The 1100D is 5.2, so it appears that with the Tamron smaller pixels, and I suppose therefore more, as the sensor size should remain the same, would be better.

Equally I could have it 110% wrong. where the hell is JamesF ?

He was the one discussing/explaining this a few weeks back.

Will point out that after I read this and fed the focal length of 2 refractors I have that would be good for imaging, no camera seemed to have small enough pixels to offer what seemed to be the optimum, I was looking at the Atix camera range. This made me suspect what I had read. Simply I would have expected astro camera makers to produce cameras with pixel sizes that correlated to imaging scopes.

[ronin]

This is the SBIG page I was reading:

https://www.sbig.com/astronomy/about-ccd-imaging/how-to-choose-your-first-camera/

Section 4 of it explains pixel size:focal length.

It was the only one I found when searching.

[LukeSkywatcher]

I have always been told that megapixals are only a must if you intend to print them off on anything larger than A4.

Ive heard similar. If the retailers on QVC are anything to go by,then megapixels are everything.

In my own experience moving from a 5MP point and shoot digicam up to a 12MP Canon 450D made a vast difference to the sharpness,clarity and detail in images. I dont do astro-imaging,so i cant really say how the whole thing works against the specs of a scope etc.

[Digz]

I don't think more megapixels necessarily equates to a better image in terms of astrophotography.

As suggested above you need to consider other factors such as pixel size and how that matches your scope in terms of focal ratio and local seeing conditions/sky darkness. I still don't fully understand it myself, so hopefully someone with a better understanding can explain it better.

If your talking about 'normal' photography then more megapixels 'may' be better, although there is still debate amongst photographers about that.

[DaveS]

For AP you need to match the pixel size to the resolution of the optics, see the thread on the best camera to use, a few threads down.

I would say that you should be looking at big fat pixels with nice deep wells and low noise. I really think that more than 12 mp in an APS C size sensor are too many, even though my 550D has 18 mp.

If it wasn't such an old, and therefore noisy, sensor I'd say the 12 mp job in my Canon 5D is fine.

Even for photography, unless you're printing above A3, or even A2, there's little need for more than 18 mp.

[Luke]

I would think a big part in the better image with the 450D Paul would be that it probably has a much bigger sensor size. I was surprised by how much larger a DSLR sensor was than the one in my bridge camera!

There are some images about like this one where you can get a good feel for how much the sensor size can vary:

http://3.bp.blogspot.com/-xy-U6g8enVQ/TwCuvoq6IhI/AAAAAAAAPLs/OwzHMDZkKB8/s1600/sensor-size-summary.png

Ive heard similar. If the retailers on QVC are anything to go by,then megapixels are everything.

In my own experience moving from a 5MP point and shoot digicam up to a 12MP Canon 450D made a vast difference to the sharpness,clarity and detail in images. I dont do astro-imaging,so i cant really say how the whole thing works against the specs of a scope etc.

[LukeSkywatcher]

I would think a big part in the better image with the 450D Paul would be that it probably has a much bigger sensor size. I was surprised by how much larger a DSLR sensor was than the one in my bridge camera!

There are some images about like this one where you can get a good feel for how much the sensor size can vary:

http://3.bp.blogspot.com/-xy-U6g8enVQ/TwCuvoq6IhI/AAAAAAAAPLs/OwzHMDZkKB8/s1600/sensor-size-summary.png

I dont doubt this. I'm really not technical minded about photography of any kind. I just know the 450D (with 2.5 times the MP of the digicam) took better images when they were compared on the same monitor (mine). 

For astro-imaging, i am not sure but i gather that its all about the sensor size and the scope you use. When you think about it..............a CCD is nothing more then a camera sensor. 

I THINK

[jordyvz]

I work in a camera shop and this is a very common question.

Now, as a note, I will be speaking more from wide field AP rather than using a scope as my knowledge isn't so good in the scoped area!

Megapixels basically determine how big you can print and how much you can crop. Higher the MP, the more you can crop or bigger you can print as there is a higher pixel density, meaning there are more MP in the image to work with.

For AP, more MP is actually a downside really (widefield) as there are more pixels available for noise to be apparent in. For example, the Canon 6D and 5D Mark III are both very good, full frame cameras with exceptional low light performance - I have the 5D Mark III and I get clean images at 10,000 ISO straight out the camera - but the 6D has slightly better low light performance, because it has 2MP less. 

I know it also comes down to the sensor and processor in the camera but that just gives you an idea.

So Mache, in short, unless you want to print rather large or crop most of the image out, don't worry about it too much, most cameras are in-between 12-22MP nowadays and are plenty for most photographers!

What camera and lens do you have? And what were you thinking about buying?

[Mache]

Thanks for all of the replies!! I still don't fully understand the pixel/arc seconds thing, it' just not going in for some reason, is there a book for dummies? heh!

I also couldn't understand if you all thought i was taking shots through the scope (4SE) i have? I'm just using the 1100D with the Tamron Lens

Thanks ronin for the info mate i just need to re-read it a few times

I work in a camera shop and this is a very common question.

Now, as a note, I will be speaking more from wide field AP rather than using a scope as my knowledge isn't so good in the scoped area!

Megapixels basically determine how big you can print and how much you can crop. Higher the MP, the more you can crop or bigger you can print as there is a higher pixel density, meaning there are more MP in the image to work with.

For AP, more MP is actually a downside really (widefield) as there are more pixels available for noise to be apparent in. For example, the Canon 6D and 5D Mark III are both very good, full frame cameras with exceptional low light performance - I have the 5D Mark III and I get clean images at 10,000 ISO straight out the camera - but the 6D has slightly better low light performance, because it has 2MP less. 

I know it also comes down to the sensor and processor in the camera but that just gives you an idea.

So Mache, in short, unless you want to print rather large or crop most of the image out, don't worry about it too much, most cameras are in-between 12-22MP nowadays and are plenty for most photographers!

What camera and lens do you have? And what were you thinking about buying?

Thanks mate, I've currently got the 1100D and Tamron 18-270 which im using at the moment... I use it for normal photography and AP. But im looking at the 700D as it has 1080p Video, flip screen, bigger screen, better specs, better everything really and its a great step up in terms of photography. I'm hoping it will work well or even better with the Tamron lens, i also have a Canon 50 mm prime 1.8 lens which is great and cheap

Whats your thoughts?

Thanks All

Mache

[happy-kat]

Magic lantern gives more video options I gather if your camera is supported.

I use my nexus to give a big screen when taking star or telescope shots hooked up to my 1100d.

[GuillermoBarrancos]

Ive heard similar. If the retailers on QVC are anything to go by,then megapixels are everything.

In my own experience moving from a 5MP point and shoot digicam up to a 12MP Canon 450D made a vast difference to the sharpness,clarity and detail in images. I dont do astro-imaging,so i cant really say how the whole thing works against the specs of a scope etc.

That has more to do with the quality of the sensor, the hardware and lens combination, than the amount of MPixels.

[DaveS]

You know, looking at your lens, I'd be more inclined to put the money toward some better optics. For any kind of AP, even wide-field DSLR AP a slow zoom like that Tamron is the last thing you'd want on the front of your camera.

Have a look at somewhere like Ffordes, who have a huge range of S/H stock, perhaps even consider an old vintage prime from another manufacturer with an adaptor to fit it to Canon. Modern lenses aren't *always* better.

[jordyvz]

Thanks mate, I've currently got the 1100D and Tamron 18-270 which im using at the moment... I use it for normal photography and AP. But im looking at the 700D as it has 1080p Video, flip screen, bigger screen, better specs, better everything really and its a great step up in terms of photography. I'm hoping it will work well or even better with the Tamron lens, i also have a Canon 50 mm prime 1.8 lens which is great and cheap

Whats your thoughts?

Thanks All

Mache

No problem, glad to help

1100D and the Tamron 18-270 is a great pair, and the Tamron is the best in it's class at the moment as a travel lens to shoot everything with. However, if you want to get better photo's over all I would suggest to get a standard lens and then a telephoto lens on top, as the more you ask a lens to do, like with the Tamron, you do unfortunately compromise on some image quality. If you don't want to spend too much, I would suggest the Tamron 70-300 VC, as it is sharper than the Canon 70-300, and you can get that for just under £300. My shop does them for £289 at the moment.

Yep, 700D is certainly a solid choice! The AF system is great, and a real lovely camera. The 50 f/1.8 is great too - I want to get one over the f/1.4 and ESPECIALLY the f/1.2 version!

But as I said, to get better image quality you're actually better off upgrading your lenses first, as the light coming through the glass is what the camera records, so by making that light as good as possible via lenses, you'll get better images. 

So, if I were you, get some glass before getting a new camera. A great set up would be a Sigma 10-20 f/4-5.6 (it is sharper than the more expensive f/3.5 version), your standard 18-55, a 50mm f/1.8 as you have, and a Tamron 70-300 VC USD.

Feel free to message me if you have any questions.

Hope that helps

[DaveS]

Not a great fan of zooms, the only one I have is the 24-105 L, which is Ok as far as it goes but I only use it for walkabout photography. for AP I'd say primes all the way. The same goes for video, which is why I've acquired a set of Leica R glass and adaptors..

[ronin]

Mache, when I went searching for the focal length to pixel relationship I expected to come out with a value of 5-6 micron for the scopes I have. Instead I ended up with 2 and nearly 3 micron. I was simply wondering which camera might best suit the scopes I have. One gave 2.9 micron the other 2.2 micron, both without a reducer.

Looked up the pixel size of the AP ccd cameras and they were up at the 5 to 6 micron size, and bigger.

Meaning that using the guide from SBIG it meant that there is little chance of getting the right "resolution" (or whatever it is called).

This made little sense to me, and still makes little sense. The implication being that AP ccd's are not matched to AP scopes. Strangely the nearest I could find was the ZWO cmos based devices.

Anyway you are talking about a DSLR and they seem to have bigger pixels so getting a DSLR with more pixels would not seem to place you at a disadvantage and very likely would be useful. I would expect the newer DSLR's to have better noise reduction and ISO ratings.

[dph1nm]

Simply I would have expected astro camera makers to produce cameras with pixel sizes that correlated to imaging scopes.

Unfortunately not, on the whole. They use commerically available chips, which means they are usually designed for terrestrial cameras.  Try getting a suitable camera for a 2m focal length scope (ok, they exist, but they are usually old chips and expensive).

If you want to image wide field though, you are going to have to throw that 1arcsec/pixel rule out of the window. A 3 degree wide field at that size would need a 10k  x 10k pixel camera!

NigelM

[Mache]

No problem, glad to help

1100D and the Tamron 18-270 is a great pair, and the Tamron is the best in it's class at the moment as a travel lens to shoot everything with. However, if you want to get better photo's over all I would suggest to get a standard lens and then a telephoto lens on top, as the more you ask a lens to do, like with the Tamron, you do unfortunately compromise on some image quality. If you don't want to spend too much, I would suggest the Tamron 70-300 VC, as it is sharper than the Canon 70-300, and you can get that for just under £300. My shop does them for £289 at the moment.

Yep, 700D is certainly a solid choice! The AF system is great, and a real lovely camera. The 50 f/1.8 is great too - I want to get one over the f/1.4 and ESPECIALLY the f/1.2 version!

But as I said, to get better image quality you're actually better off upgrading your lenses first, as the light coming through the glass is what the camera records, so by making that light as good as possible via lenses, you'll get better images. 

So, if I were you, get some glass before getting a new camera. A great set up would be a Sigma 10-20 f/4-5.6 (it is sharper than the more expensive f/3.5 version), your standard 18-55, a 50mm f/1.8 as you have, and a Tamron 70-300 VC USD.

Feel free to message me if you have any questions.

Hope that helps

Thank for that, i have some spare cash i could throw at it and could sell my Tamron and get both those lenses you recommended