9 blades are usually more expensive. Most of the high end end lens such those with constant aperture ie f/2.8... 9 blades diaphragm makes more beautiful bokeh for ur pics while 7 blades wont give u smooth, natural n beautiful bokeh as when only 7 blades to make the aperture diaphragm, is less round den the 9 blades, therefore, affects the incoming light.
i giv an example....the sigma 28-70mm F2.8 EX DG is better than Tamron AF28-75mm F/2.8 XR Di LD Aspherical (IF) is because the sigma one got 9 blades.....right???
One more thing???how is the lens construction effect the lens....
i dont understand the meaning of like 14 groups 16 elements....
can advise me...thx so much..
again...how to verify the Sigma and Tamron lens to knw whetehr is FX or not???
9 blades are usually more expensive. Most of the high end end lens such those with constant aperture ie f/2.8... 9 blades diaphragm makes more beautiful bokeh for ur pics while 7 blades wont give u smooth, natural n beautiful bokeh as when only 7 blades to make the aperture diaphragm, is less round den the 9 blades, therefore, affects the incoming light.
You cannot make that assumption. There are alot more other factors that determine whether a lens is better.
Rubbish. Don't mislead. The smoothness of the bokeh is dependent on the shape of the aperture opening, especially when stopped down. When the aperture is held wide open, it is a moot point anyway, as most, if not all openings, are round.
There are aperture openings that are round even with 7, 8, or 9 blades. Take the Canon 24-70. It has 8 aperture blades, but the bokeh you get is pretty much magical.
wht is the meaning of when stopped down...sometime heard tht this lens or tht lens is not so good when stopped down......thx...
My 2 cents, from personal observation. Feel free to correct me.
2. Number of aperture blades affect the number of points in the star when you shoot point light source at small apertures. The formula is : for even # of blades, # points = # blades. For odd # of blades, # points = 2 * # of blades. I don't know why. I'm sure the physics is available somewhere if you google.
wht is the meaning of when stopped down...sometime heard tht this lens or tht lens is not so good when stopped down......thx...
wht is the meaning of when stopped down...sometime heard tht this lens or tht lens is not so good when stopped down......thx...