Lens Question

[jan meric]

Hey guys,

I have 16-35mm L lens II canon, my question is I often find it soft, does it matter what f stop I adjust the camera (red scarlet) or does not matter like it does on my dslr camera, example f1.4 is wide open and is softer and at f5.6 i get much sharper image. So in scarlets case does the f stop matters in the sharpness cause the f stop goes all the way up to 20+ and that confuses me a bit, and what most of you keep the shutter speed at? Is 1/48th sweet spot, or do I keep the f stop fairly at 5.6 to get the sharpness and keep the shutter speed high to not over expose.

Thanks

 

[Justin McAleece]

No offense, but it sounds like you need to read a fairly introductory photography/cinematography book. These questions will definitely be answered in there. If someone explains it on here to you they would kind of be doing you a disservice because this is really stuff that you should study and know perfectly. Just so I don't get yelled at by someone though:

Lenses are almost always their best from between 2-3 stops closed down from their widest aperture to about 1 or 2 stops closed down from their tightest aperture. e.g. a 1.4 lens will probably be great from around f2.8 or 4 to f11 or 16. It might be really good wide open but that is not usually the case. Very expensive lenses perform well at any aperture.

Typically movies at 24fps are shot with a 180 degree shutter at 1/48th. Changes can definitely be made for effect though.

Good luck, and find a good photography book so that this is all second nature to you. It's of utmost importance

 

[Dr. Sassi]

To keep your sweet spot of the lens (16-35 is certainly around 5.6), you stop down with ND (Neutral Density) Filter. Here on the forum you will find a lot of tests and discussions about NDs (and the need of infrared filtering while using them) Good luck with you exploration )

 

[jan meric]

To keep your sweet spot of the lens (16-35 is certainly around 5.6), you stop down with ND (Neutral Density) Filter. Here on the forum you will find a lot of tests and discussions about NDs (and the need of infrared filtering while using them) Good luck with you exploration )

Thank you thats the answer I was looking for, someone to tell me that yes does matter even in camera settings with my canon lens, so its best I bring f stop in camera settings to f5.6 and 1/48th shutter speed, even though i can see from the histogram over exposed then I have to use nd filters?

Many thanks

 

[Dr. Sassi]

Jan,

The 5.6 is certainly a sweet spot for the lens, but it is as well a specific setting for a the "Depth of Field" distance. It might not always be preferable to have that setting for a certain image-creation.

All these (ISO, F/T-stop, Shutter-speed, ND) as well how you set up the scene by itself, is a complex formula, that needs to be kept alive in mind. To understand the relationship among these "parameters" is not hard to learn, but to master them, to gain a great image quality AND create the image that the story needs, is something that needs a lot of praxis/experience/exploration. There is not a magic formula that covers all situations, but there is certainly a lot of damage possible, if one is not spending time to get savvy with it.

This is certainly part of the "must have" core knowledge. I agree with Justin, that some good books will push you there. But just read along the forum, most of the content is excellent. Some is just based on quoting without palpable real experience. Again, this forum bursts of good and usable information. Make notes, compare, learn. Cinematography is part of the most difficult art form in existence (as Movie-making contains pretty much all other art forms ;o), so spend some time with it, if you like to get serious with this Art.

Enjoy

Sassi

 

[Will Keir]

it's a question i had too. Sometimes it's nice when people can confirm or reroute your question.

Let's see if i can put it simply:

Shoot wide open to get the shallowest (film look) depth of field.

Shoot f5.6 for the sharpest image possible.

Now you use ND filters, as "sunglasses" for your lens to bring you to your desired look. This is how you shoot f5.6 in bright sunlight.
NDs come in incremented strengths. .1 being the lowest, 1.8 on the high end. Most kits have a .3, .6. .9 with ir, 1.2 with ir for the epic.
Buy Tiffen or Schnider

Now read this thread, http://www.reduser.net/forum/showthread.php?3976-What-filters-do-you-need-for-Red-A-beginners-guide