[LFLee]

I was reading this the other day:
Secrets of the Milky Way - Jim Richardson

"Fortunately, the Milky Way is always the same exposure: 90 seconds, f2.8, ISO 3200 will always get you a nice, bright Milky Way. Or, 60 seconds, f2.8, ISO 5000 will work. Or 30 seconds, f1.4, ISO 1600 works well, too. But note that there are no 14mm f1.4 lenses. There is one 24mm f1.4 lens and it can produce some fine star images, though with somewhat limited performance in the corners. The problem to be solved with that lens is getting it in focus, which is fiendishly difficult at f1.4 in total darkness. It must be absolutely in focus. (Hint: auto focus won’t even come close.)"

So with the K-5, I thought I can make it this time since ISO6400 is OK with K-5. I went to Assateague National Sea Shore camping and try out the starry night shot. I don't have a wide f2.8 lens (DA* 16-50mm on its way) so the kit lens is my only wide angle lens.

So my settings are ISO6400, f3.5, 18mm, manual focus @ infinity, 30secs exposure, SR off, and here is the result:


edited in LR3 to add contrast, saturation, and de-noise. For some reason dark-frame substitution were turned off.

So the question, how do I get a picture that give me more bright stars on the sky?
(like the one w/ the milky way given in the link...)

Thanks,
Lee

[bdery]

Your picture is a bit soft, but still very good and well composed!

to get more of the milky way, make sure you are shooting at it (it doesn't actually fill the whole sky). Also, using a longer exposure, while it makes you run the risk of having the moving star effect, will get more light in. In that case, though, your tent would probably have blown highlights.

[mattb123]

In addition to what bdery said: Maybe if you use a light in the tent that isn't as bright you can avoid the blowout on the tent with longer exposures.

[Capslock118]

So your sig says you are from western NY.

I grew up in buffalo (hamburg) with a cottage in chautauqua.

There is a lot of light polution out there - the picture in the article you linked to was taken in utah - at a national park - where not much light exists.

You will not get the same results sorry to say. The light polution in your area will weed out all of the faintest stars, leaving only the brightest.

A longer exposure time will help for sure, but you won't get every detail like in that article.

Like he says:

The Milky Way is out there every night. But you need a really, truly dark sky like what they have at Natural Bridges National Monument in southern Utah

[Nass]

ISO, F stop and lens MM are the main determinants of your star brightness. A 50mm f1.2 (50/1.2 = 37.5) gets you more stars than a 28 f2.8 (28/2.8=10). You want the # to be higher. Longer exposures will generally get you more light pollution as well.

[jbinpg]

Also, remember that a longer lens will need shorter exposure times than a wider one. You may be able to get away with a 30 second exposure of the equatorial Milky Way at 18mm but only 8 seconds at 55mm before star trailing kicks in.

[LFLee]

Thanks for all the comments.

The pic is taken at Assateague Island National Seashore. Not buffalo, the light pollution is there (from nearby Ocean city) though.

Nass, I have a question, with fast lens like f1.2, how do you focus? In total darkness, it is not possible to do AF. Should I set focus to infinity as well?

Also, in this darkness, the exposure compensation is +5 in my K-5 in M-mode, can I control this parameter?

I will try again when I have chance to camp out in Adorondacks end of this month (and likely will get the 50mm 1.2 by then!) and make sure I use a dimmer light source in the tent...

Joel, I just move out of western NY and now in western MA. much less light pollution


Thanks for all the suggestion guys! Any tips for the post-processing?

[alohadave]

If you really want to get lots of stars in your shots, you are going to need to look at stacking pictures. A single exposure isn't going to give the deep field of stars that you want, especially anywhere with light polution (which is most of the planet).

The Cloudy Nights forums has a wealth of information on astrophotography.

Telescope Reviews: Viewing list of forums

[Nass]

Very good point by jbinpg.

In terms of focus, personally I turn all autofocus things off and go manual at infinity. Yes it's hard to find but you just have to suck it up and do it, no real shortcuts. But then I personally tend to use manual lenses which have that marked anyway, so it's easy for me - I don't know if autolenses have that marked? I'd also say forget about exposure compensation and using other than manual, sod what the meter says - try and get it as open as you can with as much sensitivity to light as you have, use manual.

Note - don't go getting a 50 f1.2 just cause I used it as an example =). You really want to think about what you're trying to shoot, and have the right field of view for that. 50 1.2 won't get you the whole milky way =). Personally I'd stick with what you've got, do lots of trial and error with that, then have a look at for example the astro pages mentioned and work out what you really need - rather than a new lens you might have more nirvana with an equatorial mount for example =)

For example a fun experiment to do would be to take two lenses, one a wide, one a telephoto, and compare what happens, how many stars you see and how bright they are at your max ISO, widest aperture and longest MM. Bear in mind that star movement will show more at the long end, but comparing a 500mm f8 with a 10mm f4 at same ISO and exposure time might surprise you =)

[LFLee]

Very good point by jbinpg.

In terms of focus, personally I turn all autofocus things off and go manual at infinity. Yes it's hard to find but you just have to suck it up and do it, no real shortcuts. But then I personally tend to use manual lenses which have that marked anyway, so it's easy for me - I don't know if autolenses have that marked? I'd also say forget about exposure compensation and using other than manual, sod what the meter says - try and get it as open as you can with as much sensitivity to light as you have, use manual.

Note - don't go getting a 50 f1.2 just cause I used it as an example =). You really want to think about what you're trying to shoot, and have the right field of view for that. 50 1.2 won't get you the whole milky way =). Personally I'd stick with what you've got, do lots of trial and error with that, then have a look at for example the astro pages mentioned and work out what you really need - rather than a new lens you might have more nirvana with an equatorial mount for example =)

For example a fun experiment to do would be to take two lenses, one a wide, one a telephoto, and compare what happens, how many stars you see and how bright they are at your max ISO, widest aperture and longest MM. Bear in mind that star movement will show more at the long end, but comparing a 500mm f8 with a 10mm f4 at same ISO and exposure time might surprise you =)

Thanks Nass... an equatorial mount looks expensive. Can you point to a thread in the astro pages?

I put focus to infinity on the kit lens (in the kit lens, the focus ring can rotate further than the infinity mark on the lens), but at that darkness, the camera exposure adjust to +5 (is there a way to not have it do this?).
In M-mode, you can control ISO, Aperture, Exposure time, but not exposure compensation?

Another rather stupid question --- should you put on filter (UV) while shooting long exposure pic?

Lee

[Stone G.]

Thanks Nass... an equatorial mount looks expensive. Can you point to a thread in the astro pages?

I put focus to infinity on the kit lens (in the kit lens, the focus ring can rotate further than the infinity mark on the lens), but at that darkness, the camera exposure adjust to +5 (is there a way to not have it do this?).
In M-mode, you can control ISO, Aperture, Exposure time, but not exposure compensation?

Another rather stupid question --- should you put on filter (UV) while shooting long exposure pic?

Lee

An equatorial mount need not cost a fortune. A small thing like this, dedicated for astrophotography:



only costs around 1/3 the price (where I come from) of an SMC-FA 50mm f/1.4 lens.

You can also find a (maybe better though less portable) used equatorial mount. I have a used Meade LX75 (computerized with dual-axis motor controls) which cost me about the same. You can se my set-up here:

About Astrophotography - and Light Pollution (II)

This, by the way is a small tutorial for those unlucky of us who do not have easy access to non-light polluted skies. Here you may also se the effect of stacking as discussed above.

Finally: A UV-filter is of no use for this type of photography - unless you use filters dedicated for the spectral lines of interest you are better off without filters.

B.R. / Steen G. B.

[krp]

Your DA 16-50 f2.8 on the way should work well for these kinds of pictures. One way to focus, is point the lens at the brightest star, switch to live view and zoom in a lot. Then turn the focus ring until that star is as small as possible on the screen. Then make sure not to bump the focus ring or you'll have to start over. I really want to take some more star trail pictures soon, but we literally have not had a clear night in a month.

[miroshi]

can you recommend some cheap f2.8 lens? if i use it only for astro photography.

in amazon i find:
Rokinon FE14M-P 14mm F2.8 Ultra Wide Lens for Pentax (Black)
and in other site:
Samyang 14mm f/2.8 IF ED MC

the widest lens i have is kit lens da 18-55 f3.5

[alohadave]

Your DA 16-50 f2.8 on the way should work well for these kinds of pictures. One way to focus, is point the lens at the brightest star, switch to live view and zoom in a lot. Then turn the focus ring until that star is as small as possible on the screen. Then make sure not to bump the focus ring or you'll have to start over. I really want to take some more star trail pictures soon, but we literally have not had a clear night in a month.

Or, just put your focus at infinity.