28mm Art vs 30mm Art / sdQH

I was asked to compare these two lenses as both have a similar focal length, but different size and weight. The 30mm was designed in 2013 for APS-C but does ok on APS-H, the 28mm was designed in 2019 for FF, and is a more serious optic.

Both are f1.4 lenses but the 30mm struggles to achieve good optical quality fully open, while the 28mm is fine fully open. The 30mm is best at and from f2.8.

The 30mm is sharp over 2/3 of its image circle. The biggest issues with the 30mm are :

- purple (/green) fringing of bright high-contrasty edges (and other edges which might not be as noticeable).

- slightly desaturated, slightly lower contrast, slight blue cast to images.

- slightly busy bokeh with a more 'drawn quality', which is ok if you like that kind of bokeh.

- edges and corners can be soft, which may not matter much with many subjects.

The above is helped by stopping down, and the purple fringing can be reduced significantly via turning on lens corrections in SPP.

Here are tripod comparisons, lens corrections turned off (so you can see the aberrations, though normally with the 30mm I'd turn lens corrections on).

The following shed photos look like 'flat tests', but of course they are not, there's variation in distance over the surfaces, so bear that in mind when scanning across the photos for sharpness.

30mm Art @f1.8...



28mm Art @f1.8...



_____________________________________

30mm Art @f4...



28mm Art @f4...



_____________________________________

30mm Art @f1.4...



28mm Art @f1.4...



_____________________________________

30mm Art @f2...



28mm Art @f2...



_____________________________________

30mm Art @f2.8...



28mm Art @f2.8...



_____________________________________

30mm Art @f1.8...



28mm Art @f1.8...



Interestingly in that large shot, which was the closest focus distance of all the above (though not the minimum focus distance of the lenses), the 30mm has a wider angle of view than the 28mm... possibly because the 28mm's barrel is physically twice the length of 30mm, so the front element was significantly closer to the subject at these distances?

All shots within each subject were developed with the same SPP settings, including fixed WB of Daylight or Overcast.

The Smooth > Crispy enhancement slider was set to minimum.

Lens Correction, Off.

All full-res. For those who wish to properly compare, I suggest you download and view in pairs, side by side, 100%.

Thanks for sharing this comparison with us.

It also seems to my eyes that the pictures with the 28mm look warmer and slightly brighter.

Krell22 said:

Thanks for sharing this comparison with us.

Click to expand...

my pleasure

Krell22 said:

It also seems to my eyes that the pictures with the 28mm look warmer and slightly brighter.

Click to expand...

yes this veiling was one of the negatives of the 30mm I mentioned...

- slightly desaturated, slightly lower contrast, slight blue cast to images.

by comparison the 28mm has more presence and dare I say it, Zeiss pop.

In terms of the above, the 30mm can benefit from a slight contrast boost and warming up, but it's always better to start closer to where you want to be. The 28mm does deliver images that are more 'there' in a fruity kind of way, boosting the 30mm doesn't quite achieve this. I still like the 30mm as it really does provide a handy combination with the sdQH (or sdQ) but if I'm not minding the extra bulk of the 28mm it's the lens of choice for me (and more so than the 50mm). While the 17-70mm C now lives on my sdQ, I very much enjoy that combination!

left eye said:

... but it's always better to start closer to where you want to be. ...

Click to expand...

Well said!

I hate the 30mm, I think it's disgraceful of Sigma to consider it an "Art" lens, it's absolutely horrible. Your pictures show exactly why, and I appreciate the possibility to finally see a comparison with the 28mm. As expected, it's in a totally different league.

The only reason I have the 30mm is that I bought an sdQ + 30mm kit (used, good price and perfect condition). I could never find the 28mm Art for a decent enough price, it's very expensive (for me at least).

Enjoy the 28mm, lovely lens.

WilyKit said:

I hate the 30mm, I think it's disgraceful of Sigma to consider it an "Art" lens, it's absolutely horrible.

Click to expand...

That's rather harsh! I see it as a small and lightweight f2.8 and I think it's astounding in that. Call it an f2.8 Contemporary would that make you happier?

WilyKit said:

Your pictures show exactly why, and I appreciate the possibility to finally see a comparison with the 28mm.

Click to expand...

The 30mm was designed for APS-C so I’m stretching its image circle boundaries using it on APS-H. Even though I’ve included wide open and f2 comparisons (on APS-H), this is for sake of seeing like for like comparisons - as the 28mm does well there. Ok the 30mm is not giving good edges wide open (centre is good though), so stop it down, I use it mostly f4 f5.6 f6.3 - that’s not a disaster… if it is a disaster to you - because you need to shoot wide open for the narrow DOF, then the 30mm isn’t a good choice, otherwise it is a good choice - especially on the sdQ (the sdQH also really).

WilyKit said:

As expected, it's in a totally different league.

Click to expand...

yep the 28mm Art is much heavier, physically longer and more bulky lens, and for full frame, so also expensive… it’s a no compromise lens.

WilyKit said:

The only reason I have the 30mm is that I bought an sdQ + 30mm kit (used, good price and perfect condition).

Click to expand...

I got the same kit, here's the first pics I took with it using the 30mm (f5.6 and f6.3), there no way you could call these results horrible!...full res...

https://www.dpreview.com/forums/post/66475083

Do you usually shoot the 30mm Art fully open? - maybe that's the issue.

I get to know every lens I have, and work with them, not against them. I've now got two copies of the 30mm Art, both perform identically - I checked very carefully, didn't find any sample variation between them, both are great... f2.8 onwards.

WilyKit said:

I could never find the 28mm Art for a decent enough price, it's very expensive (for me at least).

Enjoy the 28mm, lovely lens.

Click to expand...

...the point of it I've found it that it's excellent near fully open, f1.8, whereas other lenses often are not. Has soft creamy bokeh - which works well for closer subjects (as it's a wide angle it needs closer subject to throw the background out). When closed down, f5.6 - f8, there's little benefit in lugging its weight, then the 30mm works out just fine.

No, I never even dared to use it fully open. It just has an INSANE level of chromatic aberrations with any aperture setting, across the entire frame, worse than any ILC lens I've ever seen, by far. It's very, very unsharp overall, but that's not nearly as important as the extremely poor contrast. Shooting sunny landscapes with it gives ridiculous results, the lack of contrast is staggering. The amount of thick pink and green CA on buildings is comical. It's really a useless lens as far as I'm concerned, I've never seen anything as bad. The 35mm DG Art is in a totally different league, and it's not hugely heavier, just 200g heavier. And the 40mm Art which I also have is again in a totally different league compared to the 35mm, but it is almost twice as heavy. The 30mm DC Art is the absolute worst prime lens I've ever used, by far, and I never would have imagined that such a horrible prime lens even exists, especially by Sigma. That was quite shocking.

WilyKit said:

No, I never even dared to use it fully open. It just has an INSANE level of chromatic aberrations with any aperture setting, across the entire frame, worse than any ILC lens I've ever seen, by far. It's very, very unsharp overall, but that's not nearly as important as the extremely poor contrast. Shooting sunny landscapes with it gives ridiculous results, the lack of contrast is staggering. The amount of thick pink and green CA on buildings is comical. It's really a useless lens as far as I'm concerned, I've never seen anything as bad. The 35mm DG Art is in a totally different league, and it's not hugely heavier, just 200g heavier. And the 40mm Art which I also have is again in a totally different league compared to the 35mm, but it is almost twice as heavy. The 30mm DC Art is the absolute worst prime lens I've ever used, by far, and I never would have imagined that such a horrible prime lens even exists, especially by Sigma. That was quite shocking.

Click to expand...

Please compare this 30mm shot, taken at f4, with the 28mm shot at f4.

This is the same raw file I included in the original start post, but now with Lens Corrections ticked ON (in SPP), and a couple of other tweaks. This now looks better than the 28mm shot of the same subject at f4.

In the original post I developed both with the same settings (for 1:1 comparison), in reality one would develop for the best results based on the raw file, the lens etc and on what one sees on screen. The point being, when individually developed to show the best for the file, the 30mm Art is fine...



So download this, alongside the 28mm at f4 of the same subject, and compare 1:1.

/

It sounds like there’s something wrong with your 2nd hand copy, maybe haze inside? - I’d still deem it a very good prime, not excellent or superlative, though very good indeed.
When I compare it to Nikon lenses I was using in the 70’s it is superlative, tricky thing is now we enlarge and inspect on screens far more critically and easily that we’ve ever been able to. As to the contrast issues, no it’s not a very high contrast lens, but my copies don’t have low contrast to the extent you describe. It might be 15% off from being excellent but I can work with that, your copy sounds 75% off from great!

I don’t see it being worse overall than my 31mm Pentax Limited lens.

The CA as you say is prominent (when enlarged on a screen), though is gone when you click CA correct in post, ticking a box ain’t hard work. To optically correct CA in a lens of that size and weight (small elements) would mean trading that for resolution - which can’t be corrected in post. Having both, no CA and overall sharpness is possible, it’s the 28mm Art, twice the weight, size and price.

Oddly my copy of the 35mm Art was far far worse than the 30mm Art. The 35mm had really low contrast, softer edges, and lots of purple glow - really bad, I hated that lens (sent it back) - my experience of the 35mm matches yours of the 30mm!… I wouldn’t touch another 35mm Art with a barge pole… which makes me think there must be bad copies out there - and good copies.

This is an easy object to photograph and yet even with this, there's a lot of CA left even with the "correction", even in the middle of the frame (as you can see in that picture), and that's just lateral CA. The 28mm picture looks better and sharper, even in the middle, despite being less oversharpened. The sharpening you used is extreme and makes things look bad. It's easy to fool yourself that a lens is sharp when you use a ton of sharpening, especially with SPP which has the "crisp" processing that increases the sharpening further.

The 30mm has insane longitudinal CA that's amazingly even worse than the lateral CA, and this can't be adequately fixed. The lateral CA correction in SPP ruins colors by the way. It's not obvious with this picture because there aren't various colors with high saturation, but SPP's lens correction is very bad in that regard compared to PhotoLab for example (which sadly we can't use with sdQ pictures).

The lens I got was new by the way, only tested once by the seller. With its amount of CA and contrast loss, I can't agree that calling such a lens "good" or even "decent" makes any sense. And with your examples, sure, you won't see huge contrast loss, but take some pictures of landscapes in bright sunlight, people with bright sky behind them, reflective objects, etc. and you'll see huge differences between the lenses, far beyond 15% worse contrast. Sorry to know that your 35mm DG Art was bad. There's no doubt it's bad if the 30mm DC Art gave better results.. All aspects of the image quality should be obviously in favor of the 35mm.

By the way I highly recommend to use the "neutral" color mode in SPP in general instead of "standard", because the colors and luminance curves are much more natural in most cases. "Standard" may make some pictures look vivid in a nice way sometimes, but usually it's very unnatural, and all people's skin looks much worse and wrong, unlike "neutral".

WilyKit said:

This is an easy object to photograph and yet even with this, there's a lot of CA left even with the "correction", even in the middle of the frame (as you can see in that picture), and that's just lateral CA. The 28mm picture looks better and sharper, even in the middle, despite being less oversharpened. The sharpening you used is extreme and makes things look bad. It's easy to fool yourself that a lens is sharp when you use a ton of sharpening, especially with SPP which has the "crisp" processing that increases the sharpening further.

The 30mm has insane longitudinal CA that's amazingly even worse than the lateral CA, and this can't be adequately fixed. The lateral CA correction in SPP ruins colors by the way. It's not obvious with this picture because there aren't various colors with high saturation, but SPP's lens correction is very bad in that regard compared to PhotoLab for example (which sadly we can't use with sdQ pictures).

The lens I got was new by the way, only tested once by the seller. With its amount of CA and contrast loss, I can't agree that calling such a lens "good" or even "decent" makes any sense. And with your examples, sure, you won't see huge contrast loss, but take some pictures of landscapes in bright sunlight, people with bright sky behind them, reflective objects, etc. and you'll see huge differences between the lenses, far beyond 15% worse contrast.

Click to expand...

I agree with much of what you say, I'm on the same page. There is a marked difference between the 30mm Art and 28mm Art, in all kinds of ways, but I've never thought the 30mm a bad lens, in fact I think it's rather good. Having the 28mm doesn't make me want to use the 30mm less.

Bright landscapes seem ok with my 30mm, but things like white cars in sunshine with the lens at f1.4-f2 do produce glow, luckily that's not what I shoot, or many other bright white objects fully open - but if I did, the lens would go straight in the bin. In fact whenever I've seen glow (and expected it as I was shooting at f1.8) it's worked well artistically - but that's not an excuse, it's just how I know the lens.

Here's the bright landscape I included with the original post, now at f4 with Lens Corrections (CA) ON, no sharpness boost, no 'Crispy' boost, just the benefit of f4... looks excellent to me, a bit of CA but I'm not wanting zero CA, better than any other APS-C cameras and lenses I have, and this is a stress test for the 30mm on APS-H...



...that looks to me to be taken by more than a decent or more than a good lens.

The 30mm does have noticeable field curvature which the 28mm doesn't, so soft edges usually are soft only on a flat plane of focus (subjects maybe landscapes or flat shed walls!), but towards the edge there's usually sharpness closer to the foreground than what would be a flat plane of focus. This field curvature becomes much less noticeable from f4.

My favourite lens for the Fuji GFX medium format camera, the 32-64mm has even more field curvature - and works exceptionally well to provide greater background separation to portraits, but not a good landscape lens where horizontal vistas are concerned (though still it's a great £2000 lens).

WilyKit said:

Sorry to know that your 35mm DG Art was bad. There's no doubt it's bad if the 30mm DC Art gave better results.. All aspects of the image quality should be obviously in favor of the 35mm.

Click to expand...

...yes must have been a bad copy, but glad it led me to the more modern 28mm that definitely has better AF to boot.

left eye said:

WilyKit said:

This is an easy object to photograph and yet even with this, there's a lot of CA left even with the "correction", even in the middle of the frame (as you can see in that picture), and that's just lateral CA. The 28mm picture looks better and sharper, even in the middle, despite being less oversharpened. The sharpening you used is extreme and makes things look bad. It's easy to fool yourself that a lens is sharp when you use a ton of sharpening, especially with SPP which has the "crisp" processing that increases the sharpening further.

The 30mm has insane longitudinal CA that's amazingly even worse than the lateral CA, and this can't be adequately fixed. The lateral CA correction in SPP ruins colors by the way. It's not obvious with this picture because there aren't various colors with high saturation, but SPP's lens correction is very bad in that regard compared to PhotoLab for example (which sadly we can't use with sdQ pictures).

The lens I got was new by the way, only tested once by the seller. With its amount of CA and contrast loss, I can't agree that calling such a lens "good" or even "decent" makes any sense. And with your examples, sure, you won't see huge contrast loss, but take some pictures of landscapes in bright sunlight, people with bright sky behind them, reflective objects, etc. and you'll see huge differences between the lenses, far beyond 15% worse contrast.

Click to expand...

I agree with much of what you say, I'm on the same page. There is a marked difference between the 30mm Art and 28mm Art, in all kinds of ways, but I've never thought the 30mm a bad lens, in fact I think it's rather good. Having the 28mm doesn't make me want to use the 30mm less.

Bright landscapes seem ok with my 30mm, but things like white cars in sunshine with the lens at f1.4-f2 do produce glow, luckily that's not what I shoot, or many other bright white objects fully open - but if I did, the lens would go straight in the bin. In fact whenever I've seen glow (and expected it as I was shooting at f1.8) it's worked well artistically - but that's not an excuse, it's just how I know the lens.

Here's the bright landscape I included with the original post, now at f4 with Lens Corrections (CA) ON, no sharpness boost, no 'Crispy' boost, just the benefit of f4... looks excellent to me, a bit of CA but I'm not wanting zero CA, better than any other APS-C cameras and lenses I have, and this is a stress test for the 30mm on APS-H...



...that looks to me to be taken by more than a decent or more than a good lens.

The 30mm does have noticeable field curvature which the 28mm doesn't, so soft edges usually are soft only on a flat plane of focus (subjects maybe landscapes or flat shed walls!), but towards the edge there's usually sharpness closer to the foreground than what would be a flat plane of focus. This field curvature becomes much less noticeable from f4.

Click to expand...

Roger Cicala uses Edge Detection and grass to assess the focal plane of a lens but your shot seems to be focused on the trees:



See original size+ for the edge detection.

xpatUSA2 said:

left eye said:

WilyKit said:

This is an easy object to photograph and yet even with this, there's a lot of CA left even with the "correction", even in the middle of the frame (as you can see in that picture), and that's just lateral CA. The 28mm picture looks better and sharper, even in the middle, despite being less oversharpened. The sharpening you used is extreme and makes things look bad. It's easy to fool yourself that a lens is sharp when you use a ton of sharpening, especially with SPP which has the "crisp" processing that increases the sharpening further.

The 30mm has insane longitudinal CA that's amazingly even worse than the lateral CA, and this can't be adequately fixed. The lateral CA correction in SPP ruins colors by the way. It's not obvious with this picture because there aren't various colors with high saturation, but SPP's lens correction is very bad in that regard compared to PhotoLab for example (which sadly we can't use with sdQ pictures).

The lens I got was new by the way, only tested once by the seller. With its amount of CA and contrast loss, I can't agree that calling such a lens "good" or even "decent" makes any sense. And with your examples, sure, you won't see huge contrast loss, but take some pictures of landscapes in bright sunlight, people with bright sky behind them, reflective objects, etc. and you'll see huge differences between the lenses, far beyond 15% worse contrast.

Click to expand...

I agree with much of what you say, I'm on the same page. There is a marked difference between the 30mm Art and 28mm Art, in all kinds of ways, but I've never thought the 30mm a bad lens, in fact I think it's rather good. Having the 28mm doesn't make me want to use the 30mm less.

Bright landscapes seem ok with my 30mm, but things like white cars in sunshine with the lens at f1.4-f2 do produce glow, luckily that's not what I shoot, or many other bright white objects fully open - but if I did, the lens would go straight in the bin. In fact whenever I've seen glow (and expected it as I was shooting at f1.8) it's worked well artistically - but that's not an excuse, it's just how I know the lens.

Here's the bright landscape I included with the original post, now at f4 with Lens Corrections (CA) ON, no sharpness boost, no 'Crispy' boost, just the benefit of f4... looks excellent to me, a bit of CA but I'm not wanting zero CA, better than any other APS-C cameras and lenses I have, and this is a stress test for the 30mm on APS-H...



...that looks to me to be taken by more than a decent or more than a good lens.

The 30mm does have noticeable field curvature which the 28mm doesn't, so soft edges usually are soft only on a flat plane of focus (subjects maybe landscapes or flat shed walls!), but towards the edge there's usually sharpness closer to the foreground than what would be a flat plane of focus. This field curvature becomes much less noticeable from f4.

Click to expand...

Roger Cicala uses Edge Detection and grass to assess the focal plane of a lens but your shot seems to be focused on the trees:



See original size+ for the edge detection.

Click to expand...

...yes I've used that technique a lot to prove field curvature before (even though I could see it in shots without using enhancement).

Here is the same shot at f2.2 with sharpness on 0 (f2.2 rather than f5.6), and I've marked what I think is in good focus across the frame with no preference to keeping my indications symmetrical left to right...



In the above, it's not the best example, better would be a flat plane stretching out from foreground to distance, like a flat field or car park. In the above however the tall dead flowers the foreground 'lift the front up' making the whole plane more eye-level, compressing the test. Nevertheless you can see the focus pulling forward to the sides of the frame, especially on the right side - the is the field curvature that the 28mm doesn't have - but again this isn't the best example.

For most 'not flat' subjects some field curvature isn't an issue (and as mentioned is actually a bonus for portraits).

left eye said:

WilyKit said:

I hate the 30mm, I think it's disgraceful of Sigma to consider it an "Art" lens, it's absolutely horrible.

Click to expand...

That's rather harsh! I see it as a small and lightweight f2.8 and I think it's astounding in that. Call it an f2.8 Contemporary would that make you happier?

Click to expand...

That's probably what Sigma should have done. In fact, why couldn't they have called it an f1.4 Contemporary? It's small, light, inexpensive, and has a similar build to a Contemporary model, doesn't it? Its size and price would qualify it as a Contemporary lens, just like the 56mm f1.4 C. In fact, the new 30mm f1.4 actually is marketed as a Contemporary lens.

https://www.adorama.com/sg5614fjx.html

https://www.adorama.com/sg3014fjx.html

Frankly I don't see a whole lot of difference between the new 30mm f1.4 Contemporary and the old 30mm Art, and the new 30mm is actually cheaper than the 56mm.

left eye said:

left eye said:

Your pictures show exactly why, and I appreciate the possibility to finally see a comparison with the 28mm.

Click to expand...

The 30mm was designed for APS-C so I’m stretching its image circle boundaries using it on APS-H. Even though I’ve included wide open and f2 comparisons (on APS-H), this is for sake of seeing like for like comparisons - as the 28mm does well there. Ok the 30mm is not giving good edges wide open (centre is good though), so stop it down, I use it mostly f4 f5.6 f6.3 - that’s not a disaster… if it is a disaster to you - because you need to shoot wide open for the narrow DOF, then the 30mm isn’t a good choice, otherwise it is a good choice - especially on the sdQ (the sdQH also really).

left eye said:

As expected, it's in a totally different league.

Click to expand...

yep the 28mm Art is much heavier, physically longer and more bulky lens, and for full frame, so also expensive… it’s a no compromise lens.

Click to expand...

The 30mm is not a no compromise lens, so does not deserve thw Art lens moniker.

left eye said:

left eye said:

The only reason I have the 30mm is that I bought an sdQ + 30mm kit (used, good price and perfect condition).

Click to expand...

I got the same kit, here's the first pics I took with it using the 30mm (f5.6 and f6.3), there no way you could call these results horrible!...full res...

https://www.dpreview.com/forums/post/66475083

Do you usually shoot the 30mm Art fully open? - maybe that's the issue.

I get to know every lens I have, and work with them, not against them. I've now got two copies of the 30mm Art, both perform identically - I checked very carefully, didn't find any sample variation between them, both are great... f2.8 onwards.

left eye said:

I could never find the 28mm Art for a decent enough price, it's very expensive (for me at least).

Enjoy the 28mm, lovely lens.

Click to expand...

...the point of it I've found it that it's excellent near fully open, f1.8, whereas other lenses often are not. Has soft creamy bokeh - which works well for closer subjects (as it's a wide angle it needs closer subject to throw the background out). When closed down, f5.6 - f8, there's little benefit in lugging its weight, then the 30mm works out just fine.

Click to expand...

I almost never shoot wide open or even at f2or f2.8. Usually I shoot at f4 or f5.6 for highest resolution, or f7.1 to get greater depth of field. Do you think the 30mm matches the 28mm at those apertures?

left eye said:

xpatUSA2 said:

left eye said:

WilyKit said:

This is an easy object to photograph and yet even with this, there's a lot of CA left even with the "correction", even in the middle of the frame (as you can see in that picture), and that's just lateral CA. The 28mm picture looks better and sharper, even in the middle, despite being less oversharpened. The sharpening you used is extreme and makes things look bad. It's easy to fool yourself that a lens is sharp when you use a ton of sharpening, especially with SPP which has the "crisp" processing that increases the sharpening further.

The 30mm has insane longitudinal CA that's amazingly even worse than the lateral CA, and this can't be adequately fixed. The lateral CA correction in SPP ruins colors by the way. It's not obvious with this picture because there aren't various colors with high saturation, but SPP's lens correction is very bad in that regard compared to PhotoLab for example (which sadly we can't use with sdQ pictures).

The lens I got was new by the way, only tested once by the seller. With its amount of CA and contrast loss, I can't agree that calling such a lens "good" or even "decent" makes any sense. And with your examples, sure, you won't see huge contrast loss, but take some pictures of landscapes in bright sunlight, people with bright sky behind them, reflective objects, etc. and you'll see huge differences between the lenses, far beyond 15% worse contrast.

Click to expand...

I agree with much of what you say, I'm on the same page. There is a marked difference between the 30mm Art and 28mm Art, in all kinds of ways, but I've never thought the 30mm a bad lens, in fact I think it's rather good. Having the 28mm doesn't make me want to use the 30mm less.

Bright landscapes seem ok with my 30mm, but things like white cars in sunshine with the lens at f1.4-f2 do produce glow, luckily that's not what I shoot, or many other bright white objects fully open - but if I did, the lens would go straight in the bin. In fact whenever I've seen glow (and expected it as I was shooting at f1.8) it's worked well artistically - but that's not an excuse, it's just how I know the lens.

Here's the bright landscape I included with the original post, now at f4 with Lens Corrections (CA) ON, no sharpness boost, no 'Crispy' boost, just the benefit of f4... looks excellent to me, a bit of CA but I'm not wanting zero CA, better than any other APS-C cameras and lenses I have, and this is a stress test for the 30mm on APS-H...



...that looks to me to be taken by more than a decent or more than a good lens.

The 30mm does have noticeable field curvature which the 28mm doesn't, so soft edges usually are soft only on a flat plane of focus (subjects maybe landscapes or flat shed walls!), but towards the edge there's usually sharpness closer to the foreground than what would be a flat plane of focus. This field curvature becomes much less noticeable from f4.

Click to expand...

Roger Cicala uses Edge Detection and grass to assess the focal plane of a lens but your shot seems to be focused on the trees:



See original size+ for the edge detection.

Click to expand...

...yes I've used that technique a lot to prove field curvature before (even though I could see it in shots without using enhancement).

Here is the same shot at f2.2 with sharpness on 0 (f2.2 rather than f5.6), and I've marked what I think is in good focus across the frame with no preference to keeping my indications symmetrical left to right...



In the above, it's not the best example, better would be a flat plane stretching out from foreground to distance, like a flat field or car park. In the above however the tall dead flowers the foreground 'lift the front up' making the whole plane more eye-level, compressing the test. Nevertheless you can see the focus pulling forward to the sides of the frame, especially on the right side - the is the field curvature that the 28mm doesn't have - but again this isn't the best example.

For most 'not flat' subjects some field curvature isn't an issue (and as mentioned is actually a bonus for portraits).

Click to expand...

Good job ... great minds think alike :-D

Scottelly said:

Scottelly said:

the 28mm Art is much heavier, physically longer and more bulky lens, and for full frame, so also expensive… it’s a no compromise lens.

Click to expand...

The 30mm is not a no compromise lens, so does not deserve thw Art lens moniker.

Scottelly said:

...the point of the 28mm I've found is that it's excellent near fully open, f1.8, whereas other lenses often are not. Has soft creamy bokeh - which works well for closer subjects (as it's a wide angle it needs closer subject to throw the background out). When closed down, f5.6 - f8, there's little benefit in lugging its weight, then the 30mm works out just fine.

Click to expand...

I almost never shoot wide open or even at f2or f2.8. Usually I shoot at f4 or f5.6 for highest resolution, or f7.1 to get greater depth of field. Do you think the 30mm matches the 28mm at those apertures?

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The 30mm Art sides never really sharpen up when stopped down (especially on the sdQH) - the lens was never designed to 'stretch' that far in terms of edge resolution.

The issue when stopping down, is that the surface and placement of the aperture blades incurs internal reflections. When aperture is relatively open, the blades are out of the way, when closed down they are a notable surface v.close to the glass elements either side of them - this is the issue, light bounces off the closed blades causing a loss of contrast, notably a 'blueing' of the shadows. You'll only notice this with strong backlight subjects, especially if the shot is overexposed due to the subject being somewhat in silhouette, but it is an issue. I've done this test, strong backlight, all apertures, and a blueing will start to veil shadows the more the lens is stopped down.

As I said above the 28mm is a no-compromise lens, in all areas, inc aperture placement etc, all have been optimised to render the best image quality, under all conditions.

The 30mm even when stopped down cannot match the 28mm, in fact in the circumstances described above, strong backlight, the 30mm is better at around f2, and worse when stopped down. For strong backlight I use the 30mm at f2.

I generally don't shoot so wide open, mainly as I want to get better resolution (lenses wide open generally are a tad soft all over), but with the 28mm it's sharp from f1.4, this has opened up extra joy with photography, total flexibility to choose any aperture I want based on the subject and know I'm getting optimum results. So when you say you 'almost never shoot wide open or even f2 or f2.8', with the 28mm I think you might shoot more open more often.

If the 28mm/30mm FL works for you and is a much used FL, but you are somewhat dissatisfied with the 30mm, the 28mm is well worth it (price and weight) over the 30mm... . Hope that helps.