Megapixels and Lens hood

[0ptics]

Hello,

So I'm a beginner to photography and I was wondering does megapixel on a camera affect the IQ that much? For an example, I'm planning to purchase a bridge camera and the Canon sx40 hs has 12.1 mp, vs the Sony HV100x which has 16.2 mp. Does this mean the Sony HV100X will have much better IQ than the Canon?

Also do lens hood affect the lighting that much on cameras? On Canon's website you're able to purchase a lens hood (~$25) on the superzoom Canon sx40 hs, even though it's not a DSLR, will the lens hood be necessary for this camera or any other superzoom bridge?

Thanks!

-0ptics
​

 

[analog.universe]

Here's a thing about resolution I just posted in another thread:

"Once you get past 8 or 10 or so, more megapixels only really matter if you're going to be doing large prints at high resolution, or if you're going to be cropping off a substantial portion of the captured image. If you're cropping, that's sort of the quick and dirty way around, and you should really just have a longer lens. If you need the resolution for printing, there is absolutely no substitute. Professionals with high resolution print requirements often use medium format cameras with 50 or 80 or more megapixels. The highest quality, most expensive computer monitors are only 4 megapixel, and the more common "high resolution" monitors that come with high end computers are only 2.3. So, if your images will be most often viewed on a computer monitor, additional resolution beyond twice the resolution of the display will make no difference. Up to twice the resolution, and you may see evidence of the anti-aliasing filter in front of the sensor. If you're printing, this is a really good article on how much real estate you can get out of your sensor: How Big Can I Print by Thom Hogan"

About the lens hood... They're designed to prevent light from entering the lens that does not come from a light source that is actually in the frame. So if you're shooting outside in the sun, and the sun isn't in your photo, but it's still in front of you when you're shooting, the lens hood will keep some of that stray light out of the lens. The advantage of this is that you get higher contrast images in certain situations. When unwanted light enters the lens, you may see reflections off the internal structure of the lens, called flare. The hood reduces the number of shots in which that will happen. Some scenes however, will show no benefit at all from the hood (For example, a shot with the sun actually in the frame. Avoiding flare in those situations is solely dependant on the design of the lens). So the hood isn't "necessary" exactly, but it's pretty much accepted that you should always use one if possible, because they're so cheap. You can probably find one that doesn't have "Canon" stamped on it for even cheaper. I'm not sure how that lens is put together, but for many dSLR lenses, hoods are also helpful protecting the lens from impact and keeping dust off the front element.

 

[clanthar]

Well said by analog above.

Some more info: Some camera manufactures are guilty of pixel-stuffing. The pixels on a camera sensor are really small. They can get too small or rather so small that relative to the overall size of the sensor and resolution of the lens, IQ is actually degraded. There's a point where the only way more pixels is going to help is if you spread them out over a larger area (bigger sensor) and if you don't you may well be making the IQ worse.

Lens hoods: The day the photo industry lost it's integrity. There was a day when every lens you bought came with it's hood in the box along with the lens. The hood was an essential part of the lens and so of course the two were sold together. How could you sell a lens without an essential component? Then one day the company CEO brought the head of marketing to the factory for a tour. As they toured through the optics division MH stopped by a bench and picked up a lens hood.
"What's this he asked?"
The engineer said, "It's the hood for the 90mm."
"Why isn't it part of the lens then?" asked MH.
"It's detachable for easier storage," said E.
"Is it sold separately then?" asked MH.
E looked momentarily stunned, stammered for a moment and said, "No, no it's sold with the lens. It's not an optional component."
Of course it had never occurred to E that the two could be separated. The following month the lens hood had a box all it's own and it's own price tag.

Joe

 

[KmH]

The lens hood also accords a large measure of physical protection to your front lens element in addition to enhancing image contrast and helping to control lens flare.

The vast majority of camera maker interchangable lenses still include the lens hood. Some of the less expensive entry-level interchangable lenses do not.

P&S and bridge cameras that do not allow lens interchangability can have a problem with a lens hood because of the large zoom range the built-in lens delivers.

 

[Shutter Nutter]

Here's a thing about resolution I just posted in another thread:

If you're cropping, that's sort of the quick and dirty way around, and you should really just have a longer lens.

I agree with most of what you say BUT I rarely print at the standard ratio of 3:2 particularly for wedding clients (who actually displays at 9" x 6"?). Depending on which product they are after it's not unusual to get requests for 10"x8" or sometimes a square print just works better. I therefore try to shoot with some "crop room" at the sides when shooting in landscape orientation or top and bottom when portrait.

The other 'benefit' in shooting this way means I can lose the edges of the frame which are often optically poorer than the centre.