p.3 #1 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
Fred Miranda wrote:
I bet the big tangential mid-field dip is due to the thickness of the glass cover skewing the results on that area. The 50/1.4 ZA has a mid-field dip but perhaps its effect was exaggerated. I have tested many lenses with a mild mid-field dip being grossly exaggerated by the thicker glass cover. (WATE as an example)
Perhaps Roger can weigh in on this.
I can speculate a bit. When we first started looking at cover glass thickness it was basically the SLR to micro 4/3 lens conversions. m4/3 has a 4mm cover so that 2mm difference was pretty huge. So was the Leica film to other camera (1 to 2mm difference).
We knew that SLRs from the same manufacturer varied a bit, maybe 1.8 to 2.2mm thickness so we figured that was pretty inconsequential and basically tested at 1mm (Lecia), 4mm (m4/3) and 2mm (everyone else) and that seemed fine. Just recently, though, it was pointed out to me by a really knowledgable person that with the short backfocus distance of a mirrorless (say 18mm) the difference might be more critical than on and SLR with it's 42mm or so distance.
Looking at some lenses like this one and the FE 85mm f/1.4, we see a bit of mid-range astigmatism that looks like what we saw with those big difference in glass thickness tests. Might be paranoia, but hey, could also be real. The only answer I have is to sacrifice an FE camera, get the actual glass, and use that instead of our 2mm wafers. Which will take a while. It's hard getting the full stack of glass off the sensor without cracking it :-)
Of course, if we sacrifice some cameras, then there will be no difference. That's how the scientific method works in my hands.
p.3 #2 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
Roger - couldn't the boys at Kolari give/sell you the Sony glass when they take it off to mod a camera? Unless they end up destroying it in the process of taking it off.
p.3 #3 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
Fred Miranda wrote:
I bet the big tangential mid-field dip is due to the thickness of the glass cover skewing the results on that area. The 50/1.4 ZA has a mid-field dip but perhaps its effect was exaggerated. I have tested many lenses with a mild mid-field dip being grossly exaggerated by the thicker glass cover. (WATE as an example)
Perhaps Roger can weigh in on this.
Roger indeed mentions this is a possibility in the article.
p.3 #4 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
ecarlino wrote:
Roger - couldn't the boys at Kolari give/sell you the Sony glass when they take it off to mod a camera? Unless they end up destroying it in the process of taking it off.
Have tried Sony to see if it is important and would they have a left over piece....unless it is a deep dark secret?
p.3 #6 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
I'm baffled how many can see the negative in this lens. It has sharpness and it has smoothness without the Otus price or size. And why do we care about that slight mid-zone dip (still sharper than many 50/1.4 in the center) at f/1.4? Any dip would be likely due to field curvature, so focus adjustment would take care of that for and shallow DOF shot. I'm quite sure I will get this lens.
p.3 #7 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
joychris wrote:
Perhaps its time for another poll?
Great idea - that other poll cleaned up that other thread, which is what i'm suggesting for those that want to speculate all the time about the Sony - Zeiss relationship that is the same conversation over and over.
p.3 #8 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
ecarlino wrote:
Roger - couldn't the boys at Kolari give/sell you the Sony glass when they take it off to mod a camera? Unless they end up destroying it in the process of taking it off.
Kolari doesn't have the full sensor stack. There is still that clear glass in front of the sensor that is too risky to remove.
p.3 #11 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
hiepphotog wrote:
I'm baffled how many can see the negative in this lens. It has sharpness and it has smoothness without the Otus price or size. And why do we care about that slight mid-zone dip (still sharper than many 50/1.4 in the center) at f/1.4? Any dip would be likely due to field curvature, so focus adjustment would take care of that for and shallow DOF shot. I'm quite sure I will get this lens.
Hiep,
I don't think it's due to field curvature as according to Roger's tests, this lens is very flat field with almost no curvature. (look at the Optical Field test)
p.3 #12 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
RCicala wrote:
It's hard getting the full stack of glass off the sensor without cracking it :-)
Of course, if we sacrifice some cameras, then there will be no difference. That's how the scientific method works in my hands.
Aliexpress has new A7/A7R sensors for $250/piece. This would also allow you to get an actual measure of the thickness of the glass stacks.
It is interesting how the discussion is getting twisted with reagrds to the midfield dip. Sony who designed the lens for the E mount presumably know the glass stack thickness and would have designed it accordingly instead of a hypothetical sensor with no glass. No?
p.3 #13 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
realVivek wrote:
It is interesting how the discussion is getting twisted with reagrds to the midfield dip. Sony who designed the lens for the E mount presumably know the glass stack thickness and would have designed it accordingly instead of a hypothetical sensor with no glass. No?
It's human nature. As a group, we seem to applaud the positives while hunting for negatives.
p.3 #14 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
hiepphotog wrote:
I'm baffled how many can see the negative in this lens. It has sharpness and it has smoothness without the Otus price or size. And why do we care about that slight mid-zone dip (still sharper than many 50/1.4 in the center) at f/1.4? Any dip would be likely due to field curvature, so focus adjustment would take care of that for and shallow DOF shot. I'm quite sure I will get this lens.
Maybe, maybe not. During a faster paced portrait shoot I wouldn't want to do manual focus adjustments.
The Sigma Art looks better off center, which is more important to _me_. It will be interesting to see comparisons, as the Sony 50/1.4 is double the price of the Sigma Art.
Additionally, I think lensrentals tests at infinity and not at typical portrait distances. Will the lens be even sharper at typical portrait distances? Could be. Looks to be a very nice lens at a high price (1800Euros).
p.3 #15 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
hiepphotog wrote:
I'm baffled how many can see the negative in this lens. It has sharpness and it has smoothness without the Otus price or size. And why do we care about that slight mid-zone dip (still sharper than many 50/1.4 in the center) at f/1.4? Any dip would be likely due to field curvature, so focus adjustment would take care of that for and shallow DOF shot. I'm quite sure I will get this lens.
Sad human nature mate, nothing you can do about it.
I am very impressed with that 50mm. Not in my plans right now as my 55mm is the sharpest of 3 copies I got my hands on and have the 85mm GM on my cart but in the future....perhaps
p.3 #17 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
Fred Miranda wrote:
I bet the big tangential mid-field dip is due to the thickness of the glass cover skewing the results on that area. The 50/1.4 ZA has a mid-field dip but perhaps its effect was exaggerated. I have tested many lenses with a mild mid-field dip being grossly exaggerated by the thicker glass cover. (WATE as an example)
Perhaps Roger can weigh in on this.
That's what Roger suggested in the article. However, if that's the case, why does it dip with this particular lens and not others?
Does this mean other lenses are also stronger mid-field than Roger's charts would suggest?
I'm often shooting using rule of thirds with my 50... So it's helpful to get an accurate picture of the relative differences in performance between the lenses in this area of the frame. As it stands, this is not a strength of this new lens, but maybe I'm reading more into it than I should be. Maybe both this and the FE 55 are plent sharp mid-frame that there are more important considerations?
p.3 #18 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
virtualrain wrote:
That's what Roger suggested in the article. However, if that's the case, why does it dip with this particular lens and not others?
Does this mean other lenses are also stronger mid-field than Roger's charts would suggest?
I'm often shooting using rule of thirds with my 50... So it's helpful to get an accurate picture of the relative differences in performance between the lenses in this area of the frame. As it stands, this is not a strength of this new lens, but maybe I'm reading more into it than I should be. Maybe both this and the FE 55 are plent sharp mid-frame that there are more important considerations?...Show more →
As soon as I get a copy, I will compare the 50/1.4 ZA's center, mid-field and extreme edges to the 55/1.8 ZA and Loxia 50/2.
I usually test lenses at infinity distance and so far my results have been very similar to Roger's optical bench MTFs. That's why I use them as baseline.
p.3 #19 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
hiepphotog wrote:
I'm baffled how many can see the negative in this lens. It has sharpness and it has smoothness without the Otus price or size. And why do we care about that slight mid-zone dip (still sharper than many 50/1.4 in the center) at f/1.4? Any dip would be likely due to field curvature, so focus adjustment would take care of that for and shallow DOF shot. I'm quite sure I will get this lens.
In my case, I'm starting to try and assess if this is a worthy upgrade for my FE 55. The pros and cons are both important. I'm just trying to be realistic... not overly negative, nor overly enthusiastic. Sometimes it's a challenge to be realistic here, as by its nature, this is a forum full of enthusiasts.
p.3 #20 · LensRentals: Planar T* FE 50/1.4 ZA is absolutely superb!
Fred Miranda wrote:
As soon as I get a copy, I will compare the 50/1.4 ZA's center, mid-field and extreme edges to the 55/1.8 ZA and Loxia 50/2.
I usually test lenses at infinity distance and so far my results have been very similar to Roger's optical bench MTFs. That's why I use them as baseline.
