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Why are all Nice Sun Star Lenses MANUAL and NOT AF ? In particular 10 straight blade apertures?

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baker21

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Does anyone understand why all the 10 straight blade aperture lenses are ALWAYS manual?

Obviously sun stars is something that is subjective.. I love the 10 stars = 10 aperture straight blades, for example the loxia series...

Why is there no 10 aperture straight blade AUTO FOCUS lenses?

Can you simply not design a lense with 10 apertures blades and autofocus?

If anyone has any ideas why please let me know?

thanks
 
I've got a $800 20mm f/1.8 that has amazing sunstar ability. But its AF, and the focus throw is short with slop. Not the ideal lens for shooting night sky galaxy panoramas,. And because of the slop, I'm forced to AF in the dark to set focus.
 
baker21 said:
Does anyone understand why all the 10 straight blade aperture lenses are ALWAYS manual?

Obviously sun stars is something that is subjective.. I love the 10 stars = 10 aperture straight blades, for example the loxia series...

Why is there no 10 aperture straight blade AUTO FOCUS lenses?

Can you simply not design a lense with 10 apertures blades and autofocus?

If anyone has any ideas why please let me know?

thanks
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My take (and I'm probably wrong).

When everyone became obsessed with 'bokeh' it became important marketting to be able to say a lens has 'curved aperture blades for beautiful out of focus rendition'.

Curved aperture blades, irrespective of how many there are, do not make good sunstars.
 
tassienick said:
My take (and I'm probably wrong).

When everyone became obsessed with 'bokeh' it became important marketting to be able to say a lens has 'curved aperture blades for beautiful out of focus rendition'.

Curved aperture blades, irrespective of how many there are, do not make good sunstars.
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I think you are correct.

Modern lenses and lens designs will typically have curved blades, for the reason you mentioned.

Older lenses predate autofocus.
 
I love the sun stars the CVs, and Loxias make.. which are all 10 straight blade apertures..

I dont know why they can't make an AF lense with 10 straight aperture blades..

Must be something about the design that makes it impossible to do...
 
baker21 said:
I dont know why they can't make an AF lense with 10 straight aperture blades..

Must be something about the design that makes it impossible to do...
Click to expand...
As others have said it is a choice of the lens designers and manufacturers...
 
baker21 said:
I love the sun stars the CVs, and Loxias make.. which are all 10 straight blade apertures..

I dont know why they can't make an AF lense with 10 straight aperture blades..

Must be something about the design that makes it impossible to do...
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Just a thought... you could always learn how to focus a lens yourself.

Not hard... And will save on the whining.
 
dpcane said:
What is a Nice Sun Star Lens?
Click to expand...


From Google
From Google

They're a one-trick pony. No matter how "nice".
 

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baker21 said:
Does anyone understand why all the 10 straight blade aperture lenses are ALWAYS manual?

Obviously sun stars is something that is subjective.. I love the 10 stars = 10 aperture straight blades, for example the loxia series...

Why is there no 10 aperture straight blade AUTO FOCUS lenses?

Can you simply not design a lense with 10 apertures blades and autofocus?

If anyone has any ideas why please let me know?

thanks
Click to expand...
Why ten? Uneven number of straight blades creates double amount of sunstars.

Seven is my favourite.

Teddy
 
baker21 said:
I love the sun stars the CVs, and Loxias make.. which are all 10 straight blade apertures..

I dont know why they can't make an AF lense with 10 straight aperture blades..

Must be something about the design that makes it impossible to do...
Click to expand...
Nothing about the design that makes it impossible, just camera makers knowing their market. It’s a case of won’t, not can’t.
 
[No message]
 
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baker21 said:
I love the sun stars the CVs, and Loxias make.. which are all 10 straight blade apertures..

I dont know why they can't make an AF lense with 10 straight aperture blades..
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They can, they just choose not to for the most part. Straight blades help make more defined sun stars yes, but those straight edges also show up in out of focus highlights. Today’s market seems to prefer circular highlights/‘smooth bokeh’ to sunstars, so that’s what manufacturers build.

I’m not sure why you’re fixated on 10 blades. Five blades will create the same number of stars. Seven will create even more...
baker21 said:
Must be something about the design that makes it impossible to do...
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Given that you started this thread asking the question, it would be polite to actually read the responses... As several people have explained, there’s nothing in the design that makes it impossible.
 
baker21 said:
Does anyone understand why all the 10 straight blade aperture lenses are ALWAYS manual?

Obviously sun stars is something that is subjective.. I love the 10 stars = 10 aperture straight blades, for example the loxia series...

Why is there no 10 aperture straight blade AUTO FOCUS lenses?

Can you simply not design a lense with 10 apertures blades and autofocus?

If anyone has any ideas why please let me know?

thanks
Click to expand...
The new Pentax D FA* 50 f/1.4 gives beautiful starbursts. It's a nine blade aperture though.
 
thats a nice sun star..

Yea I think the 12-24 f4 G has 14 sun stars or maybe its 18, I forget..

I really like the Zeiss and CV 10 blade sun stars..

It hink tehy are the prettiest..

I was just wondering if it was a design issue or something, or why they never made a 10 straight blade aperture lenses with AF ...

Allt he 10 blade lenses are all manual focus..
 
TeddyD said:
Why ten? Uneven number of straight blades creates double amount of sunstars.

Seven is my favourite.

Teddy
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Never knew that. I count 14 arms from my Nikon 20mmf1.8, which makes sense. Not a sunstar connoisseur but I do like the alternating lengths of the rays in this shot.

949514b87bf14e2781d644cceb5f3289.jpg
 
baker21 said:
Does anyone understand why all the 10 straight blade aperture lenses are ALWAYS manual?

Obviously sun stars is something that is subjective.. I love the 10 stars = 10 aperture straight blades, for example the loxia series...

Why is there no 10 aperture straight blade AUTO FOCUS lenses?

Can you simply not design a lense with 10 apertures blades and autofocus?

If anyone has any ideas why please let me know?

thanks
Click to expand...
I could be wrong, but I believe it becomes a lot more challenging to have many blades on an automatic aperture. Auto lens has to be able to pop down to the set aperture and back to wide open instantly when taking a picture. Aperture blades are semi-delicate, and the more there are, the smaller they have to be. This would create high risk of damage or sticking blades. Manual lenses have smooth slow aperture movements, which mean less risk to blades and easier time managing many blades.
 
Bing Chow said:
TeddyD said:
Why ten? Uneven number of straight blades creates double amount of sunstars.

Seven is my favourite.

Teddy
Click to expand...
Never knew that. I count 14 arms from my Nikon 20mmf1.8, which makes sense. Not a sunstar connoisseur but I do like the alternating lengths of the rays in this shot.

949514b87bf14e2781d644cceb5f3289.jpg
Click to expand...
Yes, that's seven blades for sure. As for five vs ten blades would both create ten arm sunstars but with five they were two different lengths.

Teddy
 
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