35mm f1.8 vs 17-55mm f2.8

[segcamaro]

Hello All,

I am new to photography and am working to expand my gear. I just recently purchased the 17-55mm f2.8 for my camera. I am really excited to try it out when I get home from my deployment! I have read a lot of great reviews on this lens. That being said, I have also read a lot great reviews on the 35mm f1.8. I am wondering if it would be worth the money to get this lens. Any extra input from veteran photographers would be great!! BTW, I am using a D5100. The reason I am thinking that the 35mm lens would be good is for the indoor lighting. My wife and I are going to Europe for 10 days when I get back from the desert. I've heard this is the lens to have for indoor/low light pictures. What do you think? Purchase it or is it just a waste of money and use my 17-55mm.

Thank you
Shaun

 

[PaulWog]

There happens to be two 35mm 1.8G lenses. There is the DX version, and the newer FX lens. The FX one is not worth looking at, at all (too pricey, and on a D5100 it wouldn't perform any better than the DX version). Just clarifying that.

- edit: (Note, my math below might be off by just a smidge... not sure if f2.8 to f1.8 is 1 and a third stops, or 1 and a quarter... but for all practical purposes the point remains the same)

The difference between f1.8 and f2.8 is one and a third stops of light. What that means is if you needed a shutter speed of 1/50 of a second at f2.8 on your 17-55, the 35mm 1.8G at f1.8 would only need a shutter speed of 1/133 of a second to get approximately the same exposure (of course, that shutter speed would be rounded by the camera).

Alternatively, let's say you want to get 1/50 of a second shutter speed for your shot, and you're at ISO 1600. If you use f1.8 and stay at 1/50 of a second shutter speed, you could drop your ISO to about 640 and you'd be getting a similar exposure.

The 35mm 1.8G could be useful to you. The DX version is very good & has a great resale value (I sold my old one for about 90% of what I paid for it).

 

[segcamaro]

PaulWog,

Thank you for your response. I kinda grasp what you're saying. In laymen terms, I would get a better shot out of the 35mm f1.8 in low light situations because I can leave the shutter speed higher to allow more of a capture coming in? Sorry, I am very new.

Shaun

 

[tirediron]

Plainl put, the 35mm will allow you to shoot in signifcantly dimmer conditions than the 17-55 because it has a larger maximum aperture (the "hole" in the lens is larger and allows more light to enter). This means that in low lighting conditions, you can use higher shutter speeds with it than you could with the 17-55. For instance, if it's evening and using the 17-55 at it's maximum aperture of f2.8, you can only get a shutter speed of 1/30 of a second, this may not be enough to freeze movement, but with the 35 at f1.8, you could increase your shutter speed to about 1/75 of a second, which will freeze things more effectively. For it's cost, IMO, the DX version of the 35 is a worthwhile investment.