Buying a new lens - help please!

[doctorjames]

Originally Posted by spacemonkey

By primes I assume you mean lenses that are fixed and cannot zoom?


So can we all agree that the 35 f/1.8 AF-S would do the job?

Yes, prime means a fixed focal length, and for the reasons I stated in my first reply these are better for long exposure photography.


And no, we wont be able to agree that the 35mm will do the job.

It will only do that job if that is a focal length you are happy using. We cannot possibly help you there. I suggested 24mm as a starting point, but you might want to go longer or shorter than that,... its depends how you frame things and what you want to shoot and how much of the sky you want to capture.

[bigben6]

Nikon AF-S Nikkor 50mm f/1.8G Lens 2199 B&H Photo Video

Nikon AF-S Nikkor 35mm f/1.8G DX Lens 2183 B&H Photo Video

There are your two best options... BUT.... consider WHAT you are trying to shoot... if your looking for night shots great! But are looking for long or slow shutter speeds? If you looking for streaking stars, then a wider aperture is really not gonna help you... wide aperture = shorter shutter speed = no blurry stars or streaking...

so WHAT effect are you trying to acheive? And are you sure its your grea preventing you form getting that effect.... if all you want is the effect in the image you posted then yes the 35mm would prolly get the job done assuming you have room to frame your shots to our liking.... another solid options if your considering the $350 http://www.bhphotovideo.com/c/produc...AF_Nikkor.html

is the http://www.bhphotovideo.com/c/produc..._XR_Di_II.html
as it will be faster, but cover a wide wide range of focal lengths, and once you sell off your kit 18-55 its about the same as the 24mm prime, will AF with your D3100, and (IMO) be more functional all around than a prime.

[spacemonkey]

By the sounds of things I might be better off investing in a decent tripod and cable remote for the time being. Any suggestions for tripods guys?

[TheMoons678]

Willing to spend $200+ on a tripod?

Many cheap tripods have a hook where you can suspend weight from, and a release cable goes for $7 on eBay.

[Aegea]

Does the D3100 use a cable release or does it need a wireless release?

[TheMoons678]

Originally Posted by Aegea

Does the D3100 use a cable release or does it need a wireless release?

Should work, D3100 has a gps port which you use for cable releases and some battery grips.

[ccting]

Originally Posted by Aegea

Does the D3100 use a cable release or does it need a wireless release?

Currently i have USD 7 IR Wireless remote shutter release, and more expensive RF603N for that purpose, just either one. The cheaper one yeilds a few meter only, but RF603N more than 100m. I guess it is same for D5100.

For Bulb exposure, the cheaper one will do the work, but the RF603N

[photographyxfactor]

That sounds like a keeper to me. You'll be able to easily manage the shots you envision with that lens. Good for landscapes and some portrait work.

[Tzetsin]

Originally Posted by inkista

Actually, for astrophotography, I'm not sure you need a better lens than the kit, although it would be nice. But if you're stopped down and doing long exposures, chances are good, the kit is going to be decent.

The main problems are a) tracking, b) light pollution, and c) having your battery last long enough for the exposure. A really good tripod, a good tracking head or stacking images in post-processing, and living somewhere isolated without any city lights are far more key to astrophotography than the max. aperture on your lens.

You need to listen to this girl. Astro photography is about 5% lens, 40% technique and 55% software. there is no lens you can buy that will give you even close to the same result as your example image. You do not need a good tripod for astro photography, you need a good tracking head. You also need to learn the techniques used to shoot the cosmos, and you need to aquire and learn to use the image stacking software.

I dont know exactly how the example image was created, but I can tell you that there is a LOT of post processing involved. The photographer either created a composite by creating the sky with image stacking software and then adding it to another image (which is my bet) or had extremely good technique which left him with an image that had enough light to brighten the galaxy enough in post.

Using a good tripod, remote and mirror lockup will absolutely help vibration and get you clearer stars. But none of that will help your camera gather light faster.

The reason all this is needed is because the stars move extremely fast. we don't notice it so much because no one ever looks up long enough to see it move. When we point the camera skyward however you will notice just how quickly they do move and I'm sure it will surprise you.

In order to get a CLEAR shot of the sky, with no motion blur you'll have to follow the formula:

1,000 ÷ Focal Length = Maximum Shutter Speed

using a very wide angle lens will allow you more time to gather light. Higher ISO will also help you gather light. ISO is not your friend though as noise is most noticeable in black areas. the sky is black, and the stars are only a couple pixels big. Noise reduction wont work very well as it'll create banding through the very light gradients across the sky.

Lets say for example you had a 50mm lens

1000 divided by 50 = maximum exposure time of 20 seconds. But your on a crop camera. Now we have to figure out your "actual" focal length.

1.6 crop factor x 50mm = 80mm "effective" focal length.

So, 1000 divided by 80 = maximum exposure time of 12.5 seconds before you get motion blur.

12 seconds isn't a lot of time to gather light. Wider apertures will help, Higher ISOs will help, but I can assure you, from much personal experience, no amount of aperture or ISO will be enough. Wider focal lengths will also help, but obviously all celestial objects will appear much smaller.

There is software out there ( i havn't used it yet) that will allow you to take a video of the sky, enter it to the software and it will stack each frame, multiply the light and create a bright image of the sky. This is the route I suggest you go. You wont need any specialized equipment or expensive lenses. You just need to find the software, and learn how to use it.

[Tzetsin]

And read this ;D