[kamisu]

Hi, as a beginner, I have another stupid question

As far as I know, bokeh quality depends on aperture and lens build (groups/elements/blades).

I find reviews in lens data base confusing, for example Tamron 17-50 2.8 and 28-75 2.8, have bokeh ratings of 7.9 and 8.6 respectively, which is a large difference, but when I searched for comparisons between these lenses, no one mentioned any advantage regarding bokeh. Also Tamron 70-200 2.8 has a rating of 9.5 for bokeh, similar to 50 1.7 or 1.4 lenses, which is kinda hard to accept for me (considering 2.8 vs 1.4).

1. So, how can I really compare bokeh quality of different lenses ( without buying them ) ?

I have Tamrom 17-50 2.8 and I like to buy a prime with better bokeh, something not long as 50mm, but these lenses (24-28) are usually f2.8 - f/3.5, so bokeh is not as good as 50mm 1.7, so:

2. Any 20-40 mm lenses with bokeh quality close to 50mm 1.7 (below 300$) ? Thanks.

[Adam]

Bokeh is really quite subjective. Some people may like how a lens renders things, while others may not. The best thing to do is to take a shot with a lot of OOF areas and see for yourself.

[lytrytyr]

So, how can I really compare bokeh quality of different lenses ( without buying them ) ?

A lot of the reviews here include sample images which can give you some idea of the bokeh.

[vonBaloney]

Google the lenses you are interested in too -- you will often find a flickr set of samples somewhere or a discussion on the MF lens forum, etc. (Try the google "images" tab on your search if you don't get much.)

[luftfluss]

Hi, as a beginner, I have another stupid question

As far as I know, bokeh quality depends on aperture and lens build (groups/elements/blades).

I find reviews in lens data base confusing, for example Tamron 17-50 2.8 and 28-75 2.8, have bokeh ratings of 7.9 and 8.6 respectively, which is a large difference, but when I searched for comparisons between these lenses, no one mentioned any advantage regarding bokeh. Also Tamron 70-200 2.8 has a rating of 9.5 for bokeh, similar to 50 1.7 or 1.4 lenses, which is kinda hard to accept for me (considering 2.8 vs 1.4).

1. So, how can I really compare bokeh quality of different lenses ( without buying them ) ?

I have Tamrom 17-50 2.8 and I like to buy a prime with better bokeh, something not long as 50mm, but these lenses (24-28) are usually f2.8 - f/3.5, so bokeh is not as good as 50mm 1.7, so:

2. Any 20-40 mm lenses with bokeh quality close to 50mm 1.7 (below 300$) ? Thanks.

Like Adam said, bokeh is highly subjective. I think the only near-universal opinion regarding bokeh is that hard edges suck.

Also, I wouldn't say that the difference between 7.9 and 8.6 is "large", it's actually less than 10%.

Finally, don't confuse "bokeh" with "subject isolation". Subject isolation is dependent on the depth of field, whereas bokeh is the nature of the rendering of the out-of-focus area.

[Anvh]

I think the only near-universal opinion regarding bokeh is that hard edges suck.

most Pentax lenses have this kind of bokeh and see how many for example like the DA*55 or DA*60-250.
Most find the bokeh interesting and the softer kind they call boring, everyone their taste

[luftfluss]

most Pentax lenses have this kind of bokeh and see how many for example like the DA*55 or DA*60-250.
Most find the bokeh interesting and the softer kind they call boring, everyone their taste

Most lenses of all makes will, at times, produce hard-edged bokeh. The trick is to try to get it not to, as some lenses are more prone to it than others.

[Anvh]

Most lenses of all makes will, at times, produce hard-edged bokeh. The trick is to try to get it not to, as some lenses are more prone to it than others.

There are 3 types basicly.
Most of the pentax lenses have soft bokeh front and hard bokeh in the rear
balanced
hard bokeh front, soft bokeh rear (sigma lenses are often so from what i see)
Compare the DA*55 photos here with the Sigma 30mm for example, very different bokeh.

That has to do how the lens correct the light.

here you can precisely see what's going on.
About Bokeh