Testing the image circle of a lens is rather simple with a test projector but it can be somewhat subjective. There isn’t always a clearly defined hard end to an image when evaluating for coverage. Sometimes a little bit of light falloff is acceptable. A natural vignette can be pleasing but it can also blend into the limit of a lens’ image and make determining maximum coverage rather difficult. I’ve spent years compiling a list of image circles based on my own subjective opinion which was met with great thanks by most – but there has always been the inevitable email or phone call from a disgruntled cinematographer who was disappointed to find that a lens clipped a fraction of a millimeter into the frame of their image despite my records. There are variables, of course, in any analog assessment such as this. Because of this, Duclos Lenses has developed a tool that records the image circle of any lens, saving a reference image for individuals such as yourself to determine to what degree the light falloff is acceptable. Continue reading ICE BOX – Image Circle Evaluation from Duclos Lenses
Everyone knows that bigger is better. Kinda… Larger sensors are often associated with lower noise levels and generally higher quality photos while smaller sensors are associated with lower data loads and higher transfer rates but noisier and generally lower quality images. It’s a trade off at this point in technology. What a lot of folks need to remember is that there is a fundamental difference between sensor size and sensor resolution. In particular when it comes to Red cameras and their wonky formats. A lot of people including Red staff will describe lens coverage in regards to a specific resolution such as “4K” or “5K”. That’s great since they pretty much own the names and if someone is asking if a lens covers 4K, they’re usually referring to a Red One or 5K on an Epic. But that’s where things get confusing.
I say database… But it’s really just a list trying to sound official.
So basically, RED has given the world a great deal of technology at a great price. But they also induced many a headache with different sensor sizes, resolutions, specs, and names. To make things a little easier, I’m compiling a list of lenses that pass through the shop and recording their image circle, or the diameter that they will cover without vignetting. This list will simply show you what the lenses are capable of. Feel free to comment on this post if you see any discrepancies or want a specific lens added. I want this to be as accurate as possible. Also note that the sensor/format sizes are generalized. There are a ton of different industry standards. There are several dozen formats that fall under 4 perf 35mm film alone. Continue reading Lens Image Circle Database