You will only notice a change if you stop down your aperture. Like if its a f/2.8 lens, and you stop down to f/4, you will see the viewfinder darken etc.
Thanks all for the information. I can see the viewfinder darken when put to smaller aperture.
I am using 50mm f1.4 but i thought it was lock at f2.8, so when i set to f1.4, i would expect it to see shallower DOF but didn't notice that. Instead the physical aperture seems to closed up a bit, i guess my assumption of it is lock at f2.8 is wrong.
Another strange thing is that the picture capture seems to have shallower DOF then what i see from the viewfinder. Does anyone have this experience of it is just because the picture captured has been properly exposed.
i mean...if you use P mode, the cam may automatically set to f2.8 and appropriate shutter speed..
Av mode should be used to fix your aparture you set.
personally, I find it difficult to see the DOF preview through the view finder especially with large aparture..the preview does not turn darken.
except for curious reason, I never use that DOF preview thing
Canik wrote: "Another strange thing is that the picture capture seems to have shallower DOF then what i see from the viewfinder. Does anyone have this experience of it is just because the picture captured has been properly exposed....."
This is due to the fact that your eyes has an aperture. In some conditions - low light - your aperture opens up = shallower preview. In brighter conditions, your eyes aperture becomes smaller = more depth of field. This is scene dependent.
Therefore, you will see the difference in what the actual DOF through view finder and the DOF of the actual image. Not many photographers realize this. This is based on my personal observations while doing macro photography and this is one key thing to note.
However the DOF gives a close resemblance of the final image.
It seems that f1.4 is not totally wide on the lense because when i select f1.4 and press DOF, the aperture blade actually close up slightly.
I do not understand what you are writing on the whole because of your failure to express in proper terminology.
but I was once remarked by a senior bro that I was saying nonsense so I was a bit reluctant to say it again
it seems I'm only curious.. and you are serious about this..
I'll keep reading this thread anyway
For a focusing screen to work, it needs to diffuse whatever light falls on it. This also means a significant part of the diffused light will not reach the eyepiece of the viewfinder, hence the viewfinder is not super-bright.
Modern focusing screens use micorolenses or similar structures that diffuse the light only rather slightly. More light reaches the eyepiece, but ouf-of-focus images do not get effectively blurred by the focusing screen anymore.
This is a deliberate marketing-driven compromise to make the viewfinders look better than they are, while simultaneously actually degrading viewfinder performance. AF SLRs inherently suffer from dark viewfinders as a lot of light is lost due to the semitransparent primary mirror; to make AF SLRs viewfinders look less awful next to manual focus cameras, poor focusing screens are used. Old SLRs from the 70s or early 80s are VASTLY better than the current crop when it comes to manual focusing or DOF preview.
The extreme case are clear glass focusing screens - they are used e.g. in microscopy and astrophotography. The picture appears pretty much always in focus, and an entirely different method for focusing (parallax focusing) is used.
i give it a try jsut now ..
the viewfinder did turn darker .. then from there how do i know the DOF ?
does all DSLRs definitely have one?