Author Topic: Help Seeing Poor Optical Performance Please (Read 13370 times)

rlboston2009 · « **on:** October 12, 2009, 20:46 »

This entire series was denied by DT due to "Poor optical performance due to low lens quality, such as lens fringing, chromatic aberrations, uneven sharpness in focus area." I now know DT does NOT allow discussion of denials on their boards. :- )

Anyway, I'd greatly appreciate if someone could help me see it. Another image taken with the same lens was approved. Of course that's neither here nor there. I'm not objecting, I'm really new and just learning, but I can't very well correct or prevent something I'm not seeing.

Thanks!

http://www.flickr.com/photos/rlboston/4005704108/#sizes/l/in/set-72157617553107197/ [nofollow]

disorderly · « **Reply #1 on:** October 12, 2009, 22:18 »

We'd need to see something at full resolution. Whatever problem they've identified is likely visible at 100% but not when you reduce to 1024x768. I might also suggest that you'll have trouble getting a lot of images accepted if you use a point & shoot camera. Limitations of small sensors can mean a lot of noise. Finally, a large lens opening (F/5.5 according to the EXIF data) will show the limitations of your lens more than a small one will.

leaf · « **Reply #2 on:** October 13, 2009, 00:44 »

agreed, it is really hard to see what the image looks like without a 100% view, but you should be able to see good detail in the corn stalks if the image is OK.

One problem that is visible however is the blown out highlights in the corn. On all the corn cobs (or husks) there is a highlight and it is completely white with no detail. It looks like you might have increased the contrast too much while editing (unless the camera did that by itself) .... or actually it looks like the image was shot overexposed a bit, then you edited it so the image was more correctly exposed but they highlights were still blown out. If there is no information in the highlights you can't 'bring them back'

grp_photo · « **Reply #3 on:** October 13, 2009, 05:21 »

LOL no Full Resolution no Exif-Data etc. how should we comment on the technical quality

The only thing one can see it's not stocky at all would not sell at very least not often (once in a lifetime maybe) and isn't a motive that is worth the work to upload and keyword anyway at least not to a microstock site if you may can sell it once in a lifetime it's better to sell traditional or via a fine-art-print agency etc!

leaf · « **Reply #4 on:** October 13, 2009, 07:16 »

Quote from: grp_photo on October 13, 2009, 05:21

LOL no Full Resolution no Exif-Data etc. how should we comment on the technical quality The only thing one can see it's not stocky at all would not sell at very least not often (once in a lifetime maybe) and isn't a motive that is worth the work to upload and keyword anyway at least not to a microstock site if you may can sell it once in a lifetime it's better to sell traditional or via a fine-art-print agency etc!

I don't agree. Background images can sell quite well on microstock.

Lcjtripod · « **Reply #5 on:** October 13, 2009, 07:46 »

Quote from: rlboston2009 on October 12, 2009, 20:46

This entire series was denied by DT due to "Poor optical performance due to low lens quality, such as lens fringing, chromatic aberrations, uneven sharpness in focus area." I now know DT does NOT allow discussion of denials on their boards. :- )

Anyway, I'd greatly appreciate if someone could help me see it. Another image taken with the same lens was approved. Of course that's neither here nor there. I'm not objecting, I'm really new and just learning, but I can't very well correct or prevent something I'm not seeing.

Thanks!

http://www.flickr.com/photos/rlboston/4005704108/#sizes/l/in/set-72157617553107197/

What brand and model camera and which lens used? From the sample you uploaded, it has blown out highlights and wrong white balance. The rest of the claimed faults cannot be see at this small resolution.

-Larry

travelstock · « **Reply #6 on:** October 13, 2009, 08:04 »

Quote from: disorderly on October 12, 2009, 22:18

We'd need to see something at full resolution. Whatever problem they've identified is likely visible at 100% but not when you reduce to 1024x768. I might also suggest that you'll have trouble getting a lot of images accepted if you use a point & shoot camera. Limitations of small sensors can mean a lot of noise. Finally, a large lens opening (F/5.5 according to the EXIF data) will show the limitations of your lens more than a small one will.

Its a Powershot A590 IS - I agre with your comments, except not sure what you mean about the large lens opening - on a compact camera with a 1/2.5 sensor that has a "crop factor" of about 6 - f5.5 will be equivalent of about f33 on a a 35mm... you can't really stop it down!

rlboston2009 · « **Reply #7 on:** October 13, 2009, 09:51 »

OK, finding a place to dump a full size file has turned out to be trickier than I would have imagined. Thank you for your patience. I've found possibly a couple of options below.

I'm enjoying the conversation, thank you for taking the time!

It is a point and shoot, Canon Sureshot A650, my film slr just died recently although I have uploaded some film shots. I realize there are limitations with the lens, but if there are workarounds, things to avoid, or if it's actually something I'm doing in processing that would be very helpful to know.

I believe you can see image full size from the browser here as well as exif data by clicking on the "image info" link:
http://photos.rlboston.dreamhosters.com/index.php?album=2009&image=20091002_6730.JPG [nofollow]

Download from here:
http://www.mediafire.com/imageview.php?quickkey=joziyohonnz&thumb=6 [nofollow]

disorderly · « **Reply #8 on:** October 13, 2009, 10:15 »

Quote from: holgs on October 13, 2009, 08:04

Its a Powershot A590 IS - I agre with your comments, except not sure what you mean about the large lens opening - on a compact camera with a 1/2.5 sensor that has a "crop factor" of about 6 - f5.5 will be equivalent of about f33 on a a 35mm... you can't really stop it down!

I was surprised to discover that the A590 doesn't stop down any further than that; its aperture only goes from F/2.6 to F/5.5. That puts the maximum F-stop at F/16 on a 35mm. Not much room for creative DOF.

gostwyck · « **Reply #9 on:** October 13, 2009, 10:27 »

At 100% it's not good even ignoring all the blow-outs!

I really wouldn't like to try using a 2007 P&S for stock photography today. It's not impossible to do but you'll be restricted to only working in ideal conditions, having to shrink your images down (to try and get them crisper) and even then you will probably have a painfully high rejection rate. That camera was built for happy-snaps and that's what it does best.

madelaide · « **Reply #10 on:** October 13, 2009, 10:27 »

Most of what I have in microstock was taken with a A620. It has limitations, butit is a decent camera, and I expect the A650 to be the same. One limitation is noise (present in sky even at ISO50), which is perhaps worse if the A650 produces larger images - A620 is 7Mpix and sometimes I downsize for micros because of their picky standards (I have upsized for Alamy with no problems). Another limitation is chromatic aberration, especially at larger apertures.

I don't understand holgs calculation about aperture. A620's minimum aperture is f/8 and it doesn't mean infinite DOF... At f/5.6 I get a limited DOF, depending on the distance. I use f/2.8 to f/4 in many of my shallow DOF images.

b79 · « **Reply #11 on:** October 13, 2009, 11:36 »

Quote from: rlboston2009 on October 13, 2009, 09:51

It is a point and shoot, Canon Sureshot A650, my film slr just died recently although I have uploaded some film shots. I realize there are limitations with the lens, but if there are workarounds, things to avoid, or if it's actually something I'm doing in processing that would be very helpful to know.

hi, I have a Canon A650 and while it's a great little camera, it's kinda hard to take a stock photo with it: It's noisy even at lowest ISO (the sensor is so dense that the camera will apply noise reduction and the photos end up looking soft/mushy), it will blow highlights easily, and you can't stop down much to get rid of CA/PF because you'll start having problems with diffraction.
Having said that, is still possible to have pictures taken with it approved (but it won't be easy).
You can try installing the CHDK (http://chdk.wikia.com/wiki/CHDK), which will let you shoot in raw (not as good as raw from a DSRL, but still better that a jpg), but still you'll have to downsize the images before submitting most of the times.

travelstock · « **Reply #12 on:** October 13, 2009, 12:04 »

Quote from: madelaide on October 13, 2009, 10:27

Most of what I have in microstock was taken with a A620. It has limitations, butit is a decent camera, and I expect the A650 to be the same. One limitation is noise (present in sky even at ISO50), which is perhaps worse if the A650 produces larger images - A620 is 7Mpix and sometimes I downsize for micros because of their picky standards (I have upsized for Alamy with no problems). Another limitation is chromatic aberration, especially at larger apertures.

I don't understand holgs calculation about aperture. A620's minimum aperture is f/8 and it doesn't mean infinite DOF... At f/5.6 I get a limited DOF, depending on the distance. I use f/2.8 to f/4 in many of my shallow DOF images.

Well I'm confused as to why the Flickr infor page says "Canon PowerShot A590 IS" - the aperture calculations were based on that model's sensor size giving it an effective focal length multiplier of 6 - a 1/1.7 sensor will give you something like a 5 times multiplier when comparing to full frame - so an effective aperture of something like f/13 to f20 in the aerture ranges you quote. This isn't infinite aperture, so if you want to limit depth of field, its still possible, but probably more likely on macro and close-up subjects where you have a high level of magnification than when doing portraits.

The camera that's being quoted now looks to have a 6* zoom range with 12MP sensor. That's a lot of compromises in a small camera, and I think even with re-sizing and post processing you'd be pushing it to get these files accepted.

Red Dove · « **Reply #13 on:** October 13, 2009, 14:53 »

I see a lot of noise and artefacting in the 100% image.

I'm also new to the world of microstock and researched a great deal into quality requirements and camera/lens capabilities. Others may disagree but the general consensus is you will limit your success with anything less than a 10MP DSLR and a quality lens or two. There are images on stock sites taken with non-DSLR cameras but the quality control is now extremely tight for new photographers trying to get into the top sites. It's a cost but you have to invest in the very best you can afford in my experience.

Dook · « **Reply #14 on:** October 13, 2009, 16:34 »

Quote from: Red Dove on October 13, 2009, 14:53

I see a lot of noise and artefacting in the 100% image.

I'm also new to the world of microstock and researched a great deal into quality requirements and camera/lens capabilities. Others may disagree but the general consensus is you will limit your success with anything less than a 10MP DSLR and a quality lens or two. There are images on stock sites taken with non-DSLR cameras but the quality control is now extremely tight for new photographers trying to get into the top sites. It's a cost but you have to invest in the very best you can afford in my experience.

"Poor optical performance due to low lens quality, such as lens fringing, chromatic aberrations, uneven sharpness in focus area." has nothing to do with sensor quality. I own Canon 30D and it is 8MP. But I use 2.8 L lenses. Just stay at 100 ISO and you will do fine all over microstock world.

travelstock · « **Reply #15 on:** October 13, 2009, 16:56 »

Quote from: Dook on October 13, 2009, 16:34

Quote from: Red Dove on October 13, 2009, 14:53
I see a lot of noise and artefacting in the 100% image.

I'm also new to the world of microstock and researched a great deal into quality requirements and camera/lens capabilities. Others may disagree but the general consensus is you will limit your success with anything less than a 10MP DSLR and a quality lens or two. There are images on stock sites taken with non-DSLR cameras but the quality control is now extremely tight for new photographers trying to get into the top sites. It's a cost but you have to invest in the very best you can afford in my experience.

"Poor optical performance due to low lens quality, such as lens fringing, chromatic aberrations, uneven sharpness in focus area." has nothing to do with sensor quality. I own Canon 30D and it is 8MP. But I use 2.8 L lenses. Just stay at 100 ISO and you will do fine all over microstock world.

Sorry Dook, but how does using a 30D with L lenses compare to using a point and shoot exactly?

Just because the rejection reason given states "poor optical quality" doesn't mean the other things aren't sound criticisms as well. Reviewers have a range of rejection reason choices - just because they hit one rather than another doesn't mean they won't pick noise or artifacts next time.

Dook · « **Reply #16 on:** October 13, 2009, 17:05 »

I was not following the thread very well. I just wanted to say that you do not need a 10MP camera as long as you stay at 100 ISO.

cathyslife · « **Reply #17 on:** October 13, 2009, 17:25 »

The only thing one can see it's not stocky at all would not sell at very least not often (once in a lifetime maybe) and isn't a motive that is worth the work to upload and keyword anyway at least not to a microstock site if you may can sell it once in a lifetime it's better to sell traditional or via a fine-art-print agency etc!

I don't agree with this either. I worked for an agriculture-based company and I was always looking for images similar to this. I don't see how many photos can be categorized as being not-stock-worthy...I am constantly surprised at what sells well!

rlboston2009 · « **Reply #18 on:** October 14, 2009, 11:15 »

A couple of final points; Holgs is correct, my bad, it's a 590. My default iso is 80 and noise is still a huge problem so I take two things from this discussion:

1) A DSLR ASAP.

2) I need to invest some time training my eyes to see these issues which my assumption means looking at lots and lots of pictures on this board and others like it.

Thanks again everyone, for taking the time!

RacePhoto · « **Reply #19 on:** October 17, 2009, 02:18 »

Quote from: holgs on October 13, 2009, 12:04

Well I'm confused as to why the Flickr infor page says "Canon PowerShot A590 IS" - the aperture calculations were based on that model's sensor size giving it an effective focal length multiplier of 6 - a 1/1.7 sensor will give you something like a 5 times multiplier when comparing to full frame - so an effective aperture of something like f/13 to f20 in the aerture ranges you quote. This isn't infinite aperture, so if you want to limit depth of field, its still possible, but probably more likely on macro and close-up subjects where you have a high level of magnification than when doing portraits.

The camera that's being quoted now looks to have a 6* zoom range with 12MP sensor. That's a lot of compromises in a small camera, and I think even with re-sizing and post processing you'd be pushing it to get these files accepted.

Maybe part of the problem is using "effective" figures instead of real physical properties. The only thing that changes with the sensor is the size of the image, there is no magnification. Even with a crop sensor on a DSLR there is no magnification as the only thing that changes is the perception and field of view. A 50mm lens is always a 50mm lens! F/8 is always a percentage/ratio of the lens diameter, not a constant physical size.

That's why you can take a camera set to ISO 200 with the same aperture, and end up with the same shutter speed. Everything is relative and related.
Purple fringing, CA and blooming are cause by lens transmitting light at different angles so the colors are not aligned and in the second case, dark vs light areas spilling over on the sensor itself. Both will get rejections.

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Author Topic: Help Seeing Poor Optical Performance Please (Read 13370 times)

rlboston2009

disorderly

leaf

grp_photo

leaf

Lcjtripod

travelstock

rlboston2009

disorderly

gostwyck

madelaide

b79

travelstock

Red Dove

Dook

travelstock

Dook

cathyslife

rlboston2009

RacePhoto

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