a really noob question

[Blind Bruce]

My Nikon came with a kit zoom lens. This lens was good except in low light situations. So, I bought another lens of similar zoom but much more expensive with a max aperture of f2.8. Now I get satisfactory shots but with shallow DOF. So I stop down to improve the DOF.
So why did I buy the faster lens in the first place? I said it was a noob question!

 

[cherylynne1]

Generally speaking, the inexpensive kit lenses are not only slower in terms of aperture but also in autofocusing speed. They usually are not as sharp as the more expensive zooms and are more prone to distortion at the extreme ends. Color rendering may also be different. So although the settings may be the same, the image quality is likely improved.

However, do you feel there isn't any improvement? Are you looking for ways to improve? Or are you happy with the more expensive zoom but not sure why since the settings are the same?

 

[Designer]

So why did I buy the faster lens in the first place?

First of all, the 18-55mm zoom is not a terrible lens. It functions quite well in the range and for the price. I have mine on the camera almost all the time. True, it doesn't open up as wide for low light photography, but for an everyday go-to lens, it's not bad.

Now to your question. There will be times when you want that 2.8 aperture, knowing full well that your DOF will be thinner. But for normal use, you will probably be somewhat stopped down anyway, so if you happen to be at f/3.5 on the upgrade lens, it will not be at the maximum, but somewhat stopped down. This may result in a better image overall, and somewhat better than the 18-55 at f3.5.

 

[Solarflare]

If you now keep shooting your wonderful new f2.8 zoom all the time at f/8, obsessed that you want everything in focus, then indeed you have won very little. In fact maybe you should think about getting a Micro Four Thirds system or even a Nikon 1, because the smaller sensors will allow you to get everything in focus easier than your larger APS-C sensor.

If however you would think of photography as art, then shallow depth of field would give you another instrument for doing what photographers are trying to archieve in many other ways, too: reduction to the essence. For that, photographers might carefully choose their focal length used, the angle they photograph something, might arrange their flash light in order to hide less important things in the dark, etc.

Now that doesnt mean that you need to shoot your f2.8 zoom at f2.8 all the time, either. But you should realize that shallow depth of field can be something very desireable, in fact something so desireable that many people buy prime lenses with enormous apertures like f1.8, f1.4, f1.2 or even higher. Down to the famous 50mm f1.0 from Canon which was around 8000$ last time I checked, or Leicas Noctilux 50mm f0.95 which is more than 10,000$.

 

[Dave442]

Bruce, make use of the fact that now you can put more of the background out of focus while still having the ability to stop down for more DOF.

You just made the observation of why people that shoot landscape often say they do not care about having a lens faster than f/4 as they often looking for that extra DOF.

 

[Blind Bruce]

Thanks folks. I guess I just wanted to justify my decision to buy the lens. I am glad I asked the question and am glad I bought the lens. I do like to shoot with a shallow DOF but am still learning the exposure to get the lighting I want. I am going to try a forced flash with a difusser over the pop up flash. Might consider a better camera as suggested. Sometimes living alone has some advantages.

 

[jaomul]

Your new lenses gives you the option that your older lenses did not.

If you were taking photos of shots at infinity or even a good distance from yourself with items around that were similar distance, depth of field may not be so important. Now do this when it's darker, and your faster lenses at f2.8 will allow you handhold shots up to 2 stops darker than your f5.6 (say at 50mm). Also generally lenses are at there best stopped down, so your f2.8 lens is at its best at a faster setting than your kit lens

 

[Overread]

A few thoughts:

1) A newer model of camera with a better sensor will give you more usable ISOs to work with. Similarly investing time into learning proper noise removal methods in editing will further increase your potential range of ISO values that you can work with and get a good shot.
This all increases your capacity to work in low light conditions and sometimes its the only option in a given situation.

2) I would, however, suggest that a better investment might be a speedlite flash instead of a new camera. The flash gives you options to add to the lighting levels and effective use of even one flash with diffusers or bouncing the light off the wall, can really expand your options beyond just relying on the ISO and wider and wider apertures (which as you've found comes with a cost of less depth of field).

3) Remember that your new lens will also let more light in for the AF sensors, improving AF speed and accuracy indoors. A flash won't help there as the AF sensors work only with ambient light*

4) Often its going to be multiple things; a little more aperture from your wider lens; a little more ISO; a little more added light. Added together helps you avoid extremes in any one factor.



*That said there are ways to make flashes pulse light to help the AF sensors.
Further many high end flash units have a flash assist light that can be used to help the AF lock on focus**

**this light only works in one-shot AF mode not continuous AF - I say that because its often the one thing everyone forgets with AF assist lights.

 

[KenC]

a little more ISO

Yeah, this ^^^ is important. I don't know what camera you have or how you have the ISO set, but most current DSLR's handle high ISO pretty well, and if the lens has VR, then you might be surprised at what you can do in typical indoor lighting at f4 or so.

In any event, I'm sure the lens will produce technically better images, especially at the extremes of focal length or near wide-open than the kit lens, so enjoy!

 

[Designer]

Might consider a better camera as suggested.

You are forewarned; spending money on photographic gear can be addictive.

 

[mcap1972]

If you want more DOF bump up ISO or add light. There is no other way.

 

[timor]

If you want more DOF bump up ISO or add light. There is no other way.

How this is increasing dof ?

 

[john.margetts]

If you want more DOF bump up ISO or add light. There is no other way.

How this is increasing dof ?

It increases DOF by allowing you to use a smaller aperture. You could also keep ISO down, use a small aperture and keep your camera on a tripod to allow long exposures (which is my preferred technique).

www.johns-old-cameras.blogspot.co.uk

 

[timor]

If you want more DOF bump up ISO or add light. There is no other way.

How this is increasing dof ?

It increases DOF by allowing you to use a smaller aperture. You could also keep ISO down, use a small aperture and keep your camera on a tripod to allow long exposures (which is my preferred technique).

www.johns-old-cameras.blogspot.co.uk

That's the sort of explanation, which was missing from MCAP.. post. Are there any other methods of increasing dof ?

 

[Designer]

If you want more DOF bump up ISO or add light. There is no other way.

How this is increasing dof ?

It increases DOF by allowing you to use a smaller aperture. You could also keep ISO down, use a small aperture and keep your camera on a tripod to allow long exposures (which is my preferred technique).

www.johns-old-cameras.blogspot.co.uk

That's the sort of explanation, which was missing from MCAP.. post. Are there any other methods of increasing dof ?

Actually, there is more you can do:

A shorter (wider) lens, and increase the distance from your subject to the camera.

So four things to increase the DOF.

Another; use a camera with a smaller sensor, such as a cell phone camera. (Which usually has a wider lens as well.)