Rebel T6 lenses

[Sjl755]

Not sure if this part is relevant, but I'm getting Rebel T6 with 18-55mm lenses, I've been told to also get the 50mm f/1.8 lenses, so my question is: wouldn't the 18-55 be the same since it already has the 50mm in it? I apologize if this is a stupid question, but this was really bugging me.

[RobertTheFat]

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@Sjl755 wrote:
Not sure if this part is relevant, but I'm getting Rebel T6 with 18-55mm lenses, I've been told to also get the 50mm f/1.8 lenses, so my question is: wouldn't the 18-55 be the same since it already has the 50mm in it? I apologize if this is a stupid question, but this was really bugging me.

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The 18-55 is f/3.5 at the wide end, isn't it? That would make it about one stop slower than the 50mm f/1.8.

I wasn't thinking when I wrote that. 50mm is near the long end of the 18-55, so it would probably be almost 2½ stops slower than the 50mm prime.

[ScottyP]

The 18-55 is at f/5.6 on the long end, and so at the same FL as the 50mm lens (50mm) it is at f/5.6.  So the f/1.8 lens is a little more than 3 stops faster than the kit zoom so it lets in more than 8x as much light at equivalent focal lengths. 

This is useful in low light because it lets you use a shutter speed that is 8x faster.  In dim light the kit lens will be struggling and will require a lot slower shutter which can blur your photos and may force you to crank up the ISO to levels that ruin your image quality. 

And as Wadizzle mentions, the neat side effect of a big lens aperture is a shallow depth of field being in focus, so your in-focus subject "pops" while distracting backgrounds and foregrounds are blurred away. 

[Waddizzle · Accepted solution]

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@Sjl755 wrote:
Not sure if this part is relevant, but I'm getting Rebel T6 with 18-55mm lenses, I've been told to also get the 50mm f/1.8 lenses, so my question is: wouldn't the 18-55 be the same since it already has the 50mm in it? I apologize if this is a stupid question, but this was really bugging me.

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Good question, actually.  I'm sure others have wondered the same thing.

Aside from one lens being a zoom and the other a prime, there is another more significant difference.  Compare the full model numbers of the lenses.  The model number includes an aperture rating [ F / ## ] for the lenses.  The smaller the number, the wider the aperture of the lens.  Aperture describes a ratio of physical sizes between some lens components

Think of the aperture as comparable to the iris in your eye.  Your eyelid is comparable to the camera's shutter.  When you are in the dark, your iris opens up wider, in order to let in more light to the eye's retina.  The aperture of a camera lens is similar.  The wider the aperture [ the smaller the f/stop number ] the more light that can get into the camera, and reach the image sensor.

The standard kit lens, EF-S 18-55mm f/3.5-5.6 IS II lens, that comes with the T6 is good for teaching you about DSLR cameras.  It is not a high performance lens, nor is it exceptionally well built and rugged.  The kit lens performs fairly well under well lit conditions, and fairly well when used with the built-in flash.

The EF 50mm f/1.8 STM lens can perform even better under low light conditions because it's aperture can open up much wider than the standard camera kit zoom lens.   One secret to sharp pictures is grabbing as much as light as possible, in the shortest period of time as possible, with the camera set to ISO 100. 

With the 50mm lens you will be able to use faster shutter speed under the same conditions when compared with the zoom lens.  Faster shutter speed will mean less motion blur from your subjects because high shutter speeds tend to "freeze" the action.  With a slower shutter speed, the subject may have time to move a fraction, or so, which will blur the image.

Also, the wider aperture will allow you to capture photos of your subjects with more background blur and fuzziness than you could with the zoom lens.  When the foreground subject is in sharp focus, and the background is not, this tends to draw the eye to the sharply focused subject.

BTw, the 50mm focal length is nearly the ideal focal length for portrait photos with the T6.

[ebiggs1]

Everything that was said is correct...mostly.  But being new to this stuff, I would not buy the 50mil it right off.  Learn what you have first.  You may find you can't live without the 50mm f1.8 or you might find you can.  

For the exact reason the 50mil is good, like indoor low light situations, becomes a problem.  A 50 mil on a T6 is a slight telephoto.  What this means is, there might not be enough room inside to use it at all.  This is one reason I suggest you learn your camera/lens first before you start adding more gear to it.