keepcoding wrote: aCuria wrote: Immortal wrote: aCuria wrote: j4nu wrote: aCuria wrote: j4nu wrote: aCuria wrote: keepcoding wrote: aCuria wrote: keepcoding wrote:
The 50-400 looks extremely soft in that comparison against other 100-400mm lenses.
From the-digital-picture.com, left Tamron, right Sony GM (both at 400mm):
Maybe a result of the short test distance? But if it was indeed 16'ish meters then this can't be the reason...
If a lens doesn’t implement floating elements the close performance tends to be shit. I’m not sure that’s the case here.
It looks like the lens is just softer than the GM glass. It’s half the price of the 100-400GM, I wouldn’t expect it to perform similarly.
Except that some reviews show that it performs excellent (e.g. Dustin Abbott).
And when comparing the MTF of both lenses, they should basically perform the same:
The MTF charts you posted are close to useless
We have 100-130lp/mm sensors (7iv, Riv and everything in between), so MTF charts testing at 30lp/mm is not helpful
You also need real life targets that resolve 100+ lp/mm to see the difference ...
Nah, it's not that easy. In actual shooting there are too many external factors that affect final IQ, e.g. slight movement, atmospheric conditions, etc.
I mean shooting test charts, you can see it, but in real life I rarely clearly see the difference between lenses suposedly super sharp and just sharp.
Rack the shutter speed up and movement problem goes away, I know people who swear on 1/5000 minimum for wildlife with the 100-400GM
taking a portrait, atmospheric conditions don’t come into play either
Regardless, 30lp/mm is absolutely not the right target in 2022 given the cameras we are using, 70-80 lp/mm is more reasonable
Not at all. 30 lp/mm is more than enough for pretty much anything for majority of people(and photgraphers). Going to extremes makes no sense and would only add(big money) cost to an already costly glass.
btw, a FF sensor capable of exactly 30 lp/mm would have a resolution of 2160x1440, which is ~3MP!
In 2001, when Canon released the 4MP 1D they tested lenses at 30 lp/mm and this made perfect sense.
However in 2022, with 34MP sensors on the entry A7iv (100 lp/mm) should we not at least test at 70-80 lp/mm?
Aren't you forgetting the Bayer matrix? 3MP would be on a monochrome sensor, 12MP on a standard sensor.
The iso standard test charts are black and white and dont care about chroma, so if you mount a perfect lens on that A7iv sensor and point your lens at the test chart afaik you should get a reading that says 100 lp/mm
The color part is more complicated. The bayer pattern is successful in part because it captures full vertical and horizontal resolution in the green channel, the A7IV is still 100 lp/mm for vertical and horizontal green lines.
However the green channel does lose resolution for diagonal lines (A7IV = 71lp/mm)
For the red and blue channels its 71 lp/mm in the diagonal directions and 50 lp/mm in the vertical and horizontal directions.
This is why I think testing at 70-80 lp/mm is important.
Dont forget that if we consider the A7RV instead of the A7IV then all these numbers go up...
Intuitively you can
Nov 03, 2022 at 01:41 PM
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