How Much Image Quality Do You Surrender When Using Lens Adapters?

by Hugh BrownstoneLeave a Comment

    The idea of taking that huge investment in lenses some of us have and leveraging it into the latest and greatest camera bodies (L series lenses, anyone? Panasonic GH4, anyone?) is really appealing.

    REALLY appealing.

    But at least in my own case, I’ve sold off a pile of L glass as I’ve downsized to the little SL1’s and gone native. Those little EF-S STM lenses are great at what they do (autofocus for video) and are so darned…little.

    Still, I haven’t been able to part with the 50mm f1.4; the 100mm f2.8 macro; or the 28-70mm f2.8L. They are lovely on the SL1’s when I want to shoot indoors or in low light — and don’t have to rely on autofocus. There simply are no equivalents in the EF-S line.

    I even wonder if I can use ‘em on that GH4 that keeps looming larger in my mind.

    And that’s when this piece by Roger Cicala (courtesy of Dave Etchells over at Imaging Resource) — along with the assistance among others of Brian Caldwell of Metabones fame — really got me thinking.

    We may not be getting the quality we’re used to when we mix and match.

    It might get you thinking, too, as you go through your own sell/keep lens decisions – and the true cost of switching brands.

    Check it out.

    Use a lens adapter, kill the quality?

    Via Imaging Resource:

    Almost all digital sensors have some amount of optical glass placed in front of them. This optical stack may serve as protective cover glass, optical low pass filter (OLPF) and infrared filter. Silicon sensors need infrared filters to prevent infrared light from swamping the sensor and wreaking havoc on RGB color management, and OLPFs have been around more or less from the beginning, to control moiré and other aliasing artifacts. The optical stack also serves to protect the sensor from damage (easier and drastically cheaper to replace the OLPF/IR/cover glass stack than the sensor itself). It turns out it's also been a way for camera manufacturers to control the reflectivity of the sensor's surface, which can lead to unwanted flare and ghosting when film-era lenses are used on digital cameras.

    Glass from a Canon sensor stack on left and Micro 4/3 on right.

    Glass from a Canon sensor stack on left and Micro 4/3 on right.

    If you were around for the digital transition, you'll remember when various manufacturers quietly released “made for digital” lenses. Some smelled a sneaky plot to spur sales of largely identical glass. For our part, we understood that added anti-reflection coatings on the rear elements of the “made for digital” designs helped deal with the high reflectivity of the sensors, even after the manufacturer's optical stack did its job. As it turns out, though, film lenses that were designed to work without an intervening stack of OLPF/IR filter/whatever can produce inferior results on digital sensors, entirely apart from reflectivity issues. More than just a change in coatings, it appears that the basic optical formulas of some lenses were modified to improve their behavior on digital cameras. Have you ever shot digital with a favorite lens from the film era, only to be disappointed by subpar sharpness? Some of that may just be a matter of the superior resolution of modern digital sensors (they can reveal lens shortcomings that we never were aware of in the film days), but it's also possible that the problem is that your lens was simply designed for an entirely different camera environment than you're currently using it in. Thanks to the sensor's filter stack, there's a chunk of optical glass in the light path that the lens was never designed to accommodate.

    Check out full article from Roger Cicala of LensRentals.

    Via Imaging Resource via LensRentals.com

    Note: it is our policy to give credit as well as deserved traffic to our news sources – so we don't repost the entire article – sorry, I know you want the juicy bits, but I feel it is only fair that their site get the traffic and besides, you just might make a new friend and find an advertiser that has something you've never seen before

    (cover photo credit: snap from Imaging Resource)


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