Do I also need an f/1.8 lens if I already have an f/3.5-6.3?

[Randomshot99]

Totally new trying to buy gift for loved one. If I am buying the s18 - 150mm f3.5-6.3 is stm lens kit do I need the f/1.8 stm lens or is that covered in the kit range? Is there a benefit to having both? Thank you! - R

[p4pictures]

Are you planning on buying the camera and lens as a kit? If so, that's a great kit lens for the EOS R10, EOS R7, EOS R50 cameras. If you want to get the RF 50mm F1.8 STM lens too, then it is covered in the zoom lens as 50mm is in between 18 and 150mm. However it is a small compact lens that is good for low light portraits. It might be a little overkill depending on how experienced the loved one is with photography.

[AtticusLake]

Hi, and welcome to the wonderful (and sadly rather complicated) world of interchangeable-lens photography.

Your question as posted is, unfortunately, not really in a state where it can be answered. So I'll try to help you with the basic concepts here a little, and maybe you can post a clarification, and we can give you a more definite answer. OK?

But first -- please don't post the same question twice; that's only going to cause confusion. It would be better to go back and delete the other post.

So.  There are two main factors about a lens that matter -- the focal length (which determines the width of the field of view; you might think of this as "magnification"), and the f-number, which descrubes how bright a lens is (basically how physically wide it is, and hence how much light it catches; smaller f-numbers indicate a brighter lens).  In your case, 18-150mm is the range of focal lengths covered by a zoom lens, and f/3.5-6.3 is the range of brightnesses is has -- meaning it is as bright as f/3.5 maximum, when zoomed out, and less bright -- f/6.3 maximum -- when zoomed in.  (This is very typical for budget zoom lenses.)

So to some points where we could use more clarification:

• First, you need to tell us what camera you're buying lenses for. Different cameras have different lens mounts, and different sized sensors; a lens which is great on one camera may be less than optimal, or may not work at all, on another camera.
• Second, when specifying lenses, please provide as much detail as possible. "18-150" isn't enough, as there could be multiple lenses with that range of focal lengths in different lens mounts, even from different manufacturers. So copy as much info about the lens as possible, like "Canon RF-S 18-150mm f/3.5-6.3 IS STM".
• Third is the same but more so; when you say "f/1.8 stm lens", that doesn't include the focal length, so I have no idea if the zoom lens covers it or not. Actually I have no idea what lens that might be.

The simple answer is that the RF-S 18-150mm f/3.5-6.3 zoom lens is a great beginner lens for a camera with an RF-S lens mount, covering a huge range of focal lengths, so that it would be a fine starter lens all by itself.  It seems to get decent reviews, based on its low cost: https://www.digitalcameraworld.com/reviews/hands-on-canon-rf-s-18-150mm-f35-63-is-stm-review

(For a camera with a different lens mount, it might be not so good, or it might not work at all; but if it's a kit lens, it should be fine.)

The main drawback is that it's not very bright; f/3.5 at the wide end, and f/6.3 zoomed in. An f/1.8 lens would be quite a lot brighter, but without knowing the focal length, I can't say what it would be good for.  And in outdoors, daylight shooting situations, the extra brightness might count for nothing -- the fact that a lens can open up to super-bright is pointless if you never actually need the extra light.

Dooes that help?

[March411]

It may help everyone a little to know the camera body for this lens. Also, It all depends on what a person intends on photographing and what they want to achieve in their images.

The f/1.8 is a faster (brighter) lens and will allow you to capture more light when shooting at f1.8. It also gives you improved control over depth of field, and the ability to create a nice bokeh (blur) effect in your images if that is your goal. The faster f1.8 aperture will also allow you to photograph in low light without having to push your ISO up as much as your f/3.5-6.3.

Opinions vary, personally I always attempt to purchase the fastest lens within my budget. With noise reduction software doing an excellent job these days some say it is better to purchase a slower lens and let the software do the heavy lifting.

Really nobody here can tell you which one is better for you given the fact none of us know your photography style. We can offer some insight to help you decide which would work best for you.