Total Noob Lens Question: EF lens recos for Alaska cruise

[GRAYWOLF69]

I have used various P&C digital cameras, but I have minimal experience with a DSLR. I am going on a cruise to Alaska in a few months.
I am looking to rent a Rebel T7i. I am wanting to try to get some shots of wildlife and other interesting sights from the ship. Basically looking for how to pick the right telephoto lens. I do not understand how the numbers translate into anything meaningful.

*I did try to search, but only got a post about matching lens and camera, not about decoding lens labels.

[Ron888]

Hey neat.I'd forgotten that was a thing

[ebiggs1]

BTW, always shoot raw never jpg.

[GRAYWOLF69]

 this is what I took that in. So, I should shift it to just Raw?

[Ron888]

You'll likely get different answers to this because people tend to use a variety of workflows.Like you i set the camera to have both RAW and jpeg.
JPEG is convenient for browsing pictures on the computer,while the RAW version is perfect for the best images (when i get them,not often 😅)

[ebiggs1]

" this is what I took that in. So, I should shift it to just Raw?"

There is no good reason to use jpg, IMHO, none. With today cameras, editors and computers using raw is no more inconvenient than jpg. Shooting raw+jpg just uses up more space on the SD on CF cards. Does it hurt anything no I suppose not but it is just not necessary.

On the off rare chance where you may need a quick unedited transfer of images I guess you might make a case but a very slim one at that. However if that occasion arises it is a simple menu setting.

[GRAYWOLF69]

Back to the lens...which one would be better for the long range shots from ship-to-shore? (Price difference is negligible)

Sigma 150-600mm f/5-6.3 OS Sports

• Filter Size: 105mm
• f/Stop Range: f/5 - 6.3 to f/22
• Minimum Focus Distance: 102.4" (2.60 m)

Tamron SP 150-600mm f/5-6.3 Di VC G2

• Filter Size: 95mm
• f/Stop Range: f/5 - 6.3 to f/32 - f/40
• Minimum Focus Distance: 7.22' (2.2 m)

I don't plan to use filters and I have other lenses for short distance...so it basically comes down to F-stop...If I understand the description lower # = more light...which is a good thing, right?

[GRAYWOLF69]

Upon further research, lower light means cleaner pictures.
Does that make the Tamron a better lens? What does the second range (f/32-f/40) mean?
I think I get f/5 to f/22, but not the f/5 to f/32-f/40

[ebiggs1]

Don't confuse f-stop or f-ratio with focal length (FL). In the case of one of the super zooms like the 150-600mm models seen to have an open aperture of f5.  F-ratio, I.E. f5, in this instance, is a measure of how much light a lens can gather and it is an indication of how fast a lens is. The smaller numbers you asked about are how far the lens can stop down. In other words it is how much light can the lens stop from getting to the shutter. Obliviously something important in very bright situations. Most of the time we are not concerned with the brighter part of the specification as most of the time we want more light. But f40 would be a very small aperture and 99% of the time not needed or even wanted.

Now your FL (focal length or 600mm in this case) is basically the magnification the lens can offer. 100mm on a full frame camera is essentially equivalent to a 2x power binoculars. 600mm would be again roughly 12x. On your cropper it would be around 18x. "...which one would be better for the long range shots from ship-to-shore?"  You are the only one that can answer that question. To me I would want as much FL as I could get so the 150-600mm super zoom is my choice. Unless you are very close to a subject or the subject is very large, a tiny subject will still be a tiny subject in your images.

All at at 600mm.

This shot was a couple meters away.

A few feet................

A lot farther away!  😁 a whole lot farther.