Originally posted by Aristophanes You are asking for the impossible. No brand does it.
You want sharp at f/1.4-7 at $250 and 250g? No way. You are into Sigma Art lens territory. They manage to get pixel sharp wide open but at the cost of substantial weight and price.
WR and metal mounts add price. WR also definitely adds mass and bulk and perhaps focus resistance on the seals.
Flower shape hoods on the 50mm range are not really the norm. Not sure you know your research here. Generally the short barrels of the 50mm "normal" lens require a consistent round hood shape.
Manual focus rings also add cost and bulk and price, so they've mostly been kept small. Not much demand for them, TBH.
What you want is the Sigma Art or the DA*55. You just don't want the necessary piece or other compromises.
This isn't about massaging optical formulas; if you want wide open sharp you need mass and cost.
Why such a defense speak? I'm not attacking anyone. I'm just suggesting improvements and i don't think i'm beeng unrealistic. I'm not asking for a f/1 FF superzoom and i'm not asking for Sigma Art quality at pinhole weight.
I just ask for small improvements over the 125 gram 107 $ DA 50/1,8 and understand weight and cost will increase. I actually just hope (not demand) the weight and price wont be more then doubled. I don't expect Sigma Art performance and i don't expect f/1,4. I just hope for f/1,8 - f/2 and noticeable sharper then DA 50/1,8 from full aperture. I (of course) don't know how the optical formula should be changed but i would expect 1-2 special glasses and maybe 1-2 more lens elements.
WR is cheap in a prime lens with internal focus. Its basically just a rubber ring around the mount and hydrophobic surface at the sides of the focus ring. Pentax 40mm XS has metal mount and a total weight of 51 grams. It includes both a focus ring and 5 pieces of glass. How many percent of those 51 grams does a metal mount add? Lets say half the weight. Then the 50/1,8 modified to metal mount would increase its weight from 125 grams to 150 grams. Its still 100 grams left for the other improvements i ask for. The rubber ring and hydrophobic surface treatment probably weighs in at around 2 grams (and takes about 5 grams of metal from the trench in the mount). WR doesn't increase focus resistance. It actually reduces focus resistance on manual focus due to more slippery friction materials (think Teflon), and doesn't do anything to the friction when using AF.
I don't care whats the norm on hood shapes, i care whats effective and practical. In theory all hoods should be flower shaped, but in practice the corners of the flower shape would be impractically far from the lens front on tele lenses. The DA* 55mm hood is round because its a tele lens (optimized for APS-C). A 50mm optimized for FF should probably have the four indents to match the corners, just like the Sigma 30/1,4 has. Since i ask for a short lens of 3-4 cm the hood should be no longer. It should fit reversed on the lens even when its mounted. And there should also be a little gap between the reversed hood and the camera to get a grip around the lens when unscrewing the hood. With a 4 cm long lens the hood should be about 3 cm long. If thats not enough, the hood can be a two piece hood, one extending the other with a simple sliding mechanism.