Sat 27-Jul-13 11:19 AM | edited Sun 28-Jul-13 09:31 PM by jrp
Hi Guys, please have look at this image. Its not meant for anything other than practicing but you will notice the blurring around the edge of the flower at 100%. Could you tell me what is the technical name for that blurring and how do I control/avoid/edit it?
p.s sorry I am struggling to get this file to upload, perhaps you can advise on the problem without it, but I will put it in my gallery as floweredge anyway.
I'm not sure what you're referring to but the blurring at the edges are out of focus areas and caused by a shallow depth of field.
If you are referring to the magenta and green edges of the out of focus petals that is called Longitudinal Chromatic Aberrations. It is common mostly in fast lenses at high contrast edges. It can be eliminated by stopping the lens down and increasing the depth of field.
Thanks Len, that's exactly the info I needed. I have already had some useful comments and have been able to look up Chromatic Aberrations and at least have some idea of what is going on. Big help thank you
Thanks again Len, your images show precisely the effect I was trying to understand. I was shooting wide open to throw out the background but I am beginning to think that in this photography game there is price for everything and it would seem the price in this instance is LoCA? I will be back at my flowerbox tomorrow to try again. Thanks so much for the time spent helping me. Really is appreciated. Ian
The normal maximum aperture of a macro lens is between f2.8 and f4. At f1.4 it would be very difficult to get any depth of field. The closer you get to the target the more you need to stop down the lens. Even at f4 and f5.6 you'll still throw the background out of focus.
As an experiment in response to your post I took a few flower photos at different apertures with the AF 85mm f1.4 lens. In order to get close enough to fill the frame of my D800 I used a Kenko extension tube between the body and the lens.
I don't have any live flowers around the house at the moment so I used a silk flower. Here's the full frame shot at f4. The background is still out of focus but most of the flower is enough in to make the photo more interesting. I also took the same photo at f1.4 and the LoCA was visible at the top edge of the flower.
Actually the OP is looking for just the opposite, putting the background out of focus without getting into CA problems with his 85mm lens. I personally don't like full dof in my macro photos. However when I want to extend the dof in my photos I use the tilt feature in my PC 85mm f2.8 micro.
HI Len, quick update. I set up camera on tripod this morning with the 85mm and took a series of shots varying only the aperture and having gone through the results I can see precisely the effect and results you have referred to. I also looked up reviews on the 85mm 1.4 and one writer quotes as follows
Well, this can be really nasty in high contrast situations, and it may need post-processing."
Of course this is a fantastic Lens(well in my view anyway) and I am not at all dissatisfied I was just curious about the effect, what it is and how you control it. I am grateful for your guidance and I have enjoyed learning a little about another facet of this fascinating hobby, or should I say growing obsession
To post the image, resize it to 900-1000 pixels on the long side. Then save it at a medium to lower quality setting to reduce the file size as needed - typically 150-200 kb. Be sure to retain EXIF data if possible.
When you are trying to look a something as detailed as the edge of a flower, also post a 100% crop so we can see the detail. Starting with the full size image, you can either manually crop to approximately a 100% view and follow the steps above. Or you can simply take a screen shot, paste it into a document or blank email, then save the image into a JPEG format for posting. You'll still need to follow the steps above to resize it for posting.
As a general rule of thumb, anything I share online is handled with these same steps to resize and save at a medium quality. That protects against theft and makes it easy to upload the small file. I find the same images tend to be used on Facebook and other ways to share, so all the small copies go into a single folder called Web Posts with a subfolder for each year. I synch this folder to my iPad, iPhone, and use it as a source of desktop backgrounds and screensavers. It is very rare for me to share a full sized file outside of client use.
Sat 27-Jul-13 02:37 PM | edited Sat 27-Jul-13 02:40 PM by icslowmo
Has been said, after looking at the image, the blur/soft edges of the flower or from a narrow depth of field as you shot this with a 85mm f/1.4 @ f/1.4 which will produce very narrow DOF given the distance to subject is reduced to fill the frame. What you have to remember is as you get closer to a subject, you will have to stop down to increase DOF if you want all of the subject in focus. For this shot:
I would suggest trying it again at say f/4 or f/5.6 to get more depth of field which will have more of the flower in focus.
Also, for posting images the limits are 1200 pixel long edge with a max size of 300kb. Or like I did above is copy the forum link from the gallery picture and past it in here.