Best 40mm Lens For F Mount
Related Reviews
jason russell
5
Best I’ve used
Best phone mount I have used, would recommend to anyone
03/12/2022
Amanda Nagle
5
Best car mount out there
Best car mount out there! not that i've tried many others, but I have used one that hooks up to the vent which isn't very sturdy and requires two hands every time you want to put your phone on it, to make sure it doesn't pop off of the vent. The steely car mount is so easy and very small. I don't like the look of those big bulky ones. My fiancé and I both have these in our cars, and just recently bought them for our mothers, who also love them!
17/11/2022
Hollywood Atlanta
5
100% Nice Lens
Best Canon Lens, I think, it all depends on what your shooting.
16/05/2022
Brenda Craig
5
Works perfectly
Can't believe I got this for.99 cent!! It works perfectly and I love interacting with my Alexa!
21/03/2022
Kevin Cross
5
Nice monocular for the price
First off, I would note that all of the negative reviews of this monocular reflect the writer's lack of knowledge of what optical specifications mean and/or the inability to use and adjust a scope for the optimum clarity. This product is exactly as described for size, weight and power. The 40mm objective lens provides for a very good image in low light. The adjustable eyepiece is convenient for eye glass wearers. I was very impressed with the quality of the scope and optics at this price level. The body has a rubberized texture and knurled surfaces on the adjustment points. It feels solid and should hold up to minor abuse. although it is a little heavy, it is about the weight you would expect for it's size. I was able to zero in and get a sharp image with little fuss. Although one can view at 30x magnification with a minimal amount of shakiness, the ability to attach a tripod is helpful for extended viewing. The monocular is easy to slip in a pocket or carry with the included lanyard. It comes with a case that has a belt loop attachment. It has lens covers although they do not have a tether attachment meaning they can be easily lost or misplaced. You can do much better for a monocular if you're willing to spend more money. At $30 for this one though, you can't go wrong. You are getting a 40mm objective lens, BAK4 prism, fully coated lenses and lots of other useful features making it an ideal scope for all kinds of activities.
23/12/2021
Customer
5
Awesome
Have had my previous ones for.10 years so was afraid to.purchase. these are better than the first
25/08/2021
Abraham Dorantes
5
Just amazing!
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 Best lens ever!
06/08/2021
Kaushal Shrestha
5
One of the best lenses for Canon
This lens is amazing. It's one of the L-series canon lens, and the feel of L lenses are completely different to the non-L ones. 17-40mm covers most of the general need, for example gathering of people, party, celebrations, portrait and close ups. f/4 is again enough unless you want to reduce the depth-of-view, which generally would be a nice feature to have, but the price difference between the 17-40mm f/4 vs 16-35mm f/2.8 makes the former a better worth for money. The main reason I like the L-lenses, apart from the solid build, is the fact that the lens system does not protrude out of the lens body during zoom, unlike the EF-S and EF (non L) lenses. This not only makes it more durable, but also helps when you have a polarizer attached to the lens, and you don't have to constantly adjust the polarizer as you change the zoom.
12/07/2021
Related Faq
Q
What kind of aa batteries can be used? there are rechargeable nickel-zinc that are 1.6v but hold their charge longer. if not these, what's recommended
A
The camea can take 1.6v rechargeable batteries, but in general rechargeable battery might drop its voltage quick depend on its physical performance. In the cold weather, recommend using Energize lithium batteries to get longer lifetime. 
Q
What lens hood will work for this filter?
A
I have the 77mm version of this and I am NOT able to use a lens hood on my Canon 17-40mm wide angle once the filter is on. I haven't tried putting on the hood first and then trying to screw on the filter yet. That's not to say that all lens hoods won't work but for me it does not under the scenario described above. 
Q
Will this work on my sony a6000 and tokina minolta 100-300mm macro zoom?
A
Yes 
Q
Too loose/there is gap between lens and adapter ring
A
  1. If there is ever any more than a slight amount of rotational play, you may want to try tightening the lens mount adapter so it will hold the lens tighter to the mount. There are 3 flanges in the middle of the adapter (what the lens locks onto) that are split open slightly, this gap is what gives the tension that holds the lens tight to the body. Over time and with use these gaps decrease in size, no longer pulling the lens tight to the adapter, which allows the lens to move inside the mount more than it should.
  2. To tighten the fit, get a slim metal object (a #1.5 or #2.0 small flat eyeglass screwdriver is ideal) and insert it into the slit to open it up just a little bit (see images below, make sure to do it to all 3 evenly). The more you open the gap, the tighter the lens will be to the adapter; too much and the lens will have a hard time mounting so make sure to do it just a little bit at a time to all 3 flanges evenly, it doesn’t take much at all to get a tight fit.Note: please do not use too much strength, or the shrapnel will be damaged.
 
Q
Is this suitable for sky gazing/ astronomy? Thank you.
A
I would say...a qualified "yes." You are going to have a nice wide field-of-view and sharp focus. The 40mm objectives are not going to allow a huge amount of light gathering but you will have portability and that counts for a lot - a light, sharp and accurate optic is more useful than a large and bulky choice. Even if that means giving up some "reach." 
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