Know your gear- Digital Camera Basics.

[graciousness]

Waste. Of. Breath.

[ccting]

Control variables : f/5.6, 1/80s, iso 200, D5100, assume that YN465 performs constantly.
The shutter speed at 1/80s is sufficient to eliminate camera shake (>1s/(50 X1.5)).


18-55mm vr kit len. The surface texture reveals with family of angles lighting with diffuse light source (bounce at wall on -camera)


50mm f/1.4. Background looks soft...darker at same f-number compared to vr kit len. Extremely Soft towards the edge matches its MTF Curve.

Grace, I think you misunderstand what i meant. I mean, if the professional lens have sweet points at widest aperture, then good, otherwise,they should improve them..(for me). It aligns with your statement "Sharpness is everything", right? For example, 50mm f/1.4 professional lens should have sweet point @ f/1.4 and not f/5.6! The only reason that lead me to purchase these expensive lenses is for widest aperture, not the aperture that my cheap vr kit lens have! If these lenses are not sharpest at wider aperture, what is the point? Of course they are rain-resistence, etc etc but they are secondary reasons, that is not solid reason for me to have them (except 35 mm f/1.8 and 70-200 VR 2)

Back to Ken's statement: "This VR kit len works like USD2000 professional len"... somehow it is true.. Even the MTF curve for those professional lens are not convincing for (1.5 cropped sensor).

[litenphrame]

Thank you for the good information. I really appreciate the research and the time you spent SK66. A VERY interesting read and full of useful information, if used properly. The information gave me an explanation of why aberrations are found.

The manufacturers are NOT going to give us any of the real numbers for obvious reasons (think corporate secrecy). We can test what we have and form our own conclusions and that may be the BEST way to "know" our individual system. Also understand, with mass production there will be variations throughout the production process, and those variations are going to be unique to each camera, lens, light, etc. USE your gear and learn it. If you get new gear, do the same. The math can only be used as a rule of thumb in this case, with the caveat that your mileage may vary.

Another note, we are talking digital here, one's and zero's, there are no 1/2's or 1/3's in digital bits, only one's and zero's. You cannot have a part of a transistor, it is either on or off. Levels of on or off are really not equal or usable (think switching noise-NOT the same as photon noise). When one of the settings is manipulated (SS, Aperture, ISO) some transistors are turned on and others are turned off or multiplied (cascaded). Think of it this way......Remember the shampoo commercial where one person tells someone and that person tells someone, etc. that is the binary principle. The camera is the ultimate recording device. The lens is only a "microphone" for the recorder.

MY point? The resulting numbers for each of the factors are a reflection of the digital (binary) effect of the change made within the camera (or the input by the lens, which ultimately is a change in the camera). Finding the "sweet spot" for your camera and lens combination is something you must do for yourself with your equipment. Yes, there will be common variations between models, but there are numerous variations within the one model (camera or lens). For example (not exactly a fitting one); I have witnessed a variation in exposure levels using the same camera body and different lenses. My kit lens requires me to set the exposure level down a third of a stop, whereas I can center the exposure level using both my 50mm and 28-105mm. Is it the lens or the camera body? Odds are the lens is the differential. If I had another kit lens maybe I would know for sure, but I do know this kit lens on this body.

SK66 provided some basic information to explain the chromatic differences when changes are made and the effect on IQ. Again, use it as a rule of thumb and test your equipment.