Hi Phoenix,

That is an old graphic trick to keep images sharper if you have to size down. This gets into the DPI vs dimensional size area.

When sizing down you are removing pixels from the image. When this is done,  photoshop interpolates the resulting image to best approximate the original. If you size down in one big swoop the image will suffer in quality. Applying unsharpen at this point will help but the image will quicky become contrasty with a small amount of unsharpen and you will end up with a crappy image. If you do this in steps you can minimize this effect.

I have done some more testing and I think that you should restitch the image in PW to the correct size you need instead of sizing down in photoshop. I have good results sizing down but after further testing I think its best to stitch in the size you need.

I display at 500 pixels wide. I have found that the following makes a great image at this size.

Stitch at 2000x1000. Output the pano at 500x375 using 80 - 90 percent compression. This yields a final pano at around 400k. This image is better than stitching at 1400x700 and using 95 percent compression.

Stitching at 1400x700 and displaying at this size(500 wide) makes a very soft image. I have not tried it but I believe 1400x700 size is best for small panos displayed at 300 pixels wide or less.

Gen. Lee.

Gen :

in your previous reply... you mentioned that you acutally use photoshop to size down the image with unsharpen mask ... can you please advice me the actually steps how to perform it ? May be you can point me to some website regarding this task. tks

"""If I want to display the image larger than 500 pixels wide I make the pano at 4000x2000. Open in Photoshop and size it down in steps applying the unsharpen mask each time at about 10 percent. I take it down to say 2000x1000. That is 1/2 half the original size. I do this in 3 or 4 steps. On the last step I apply a little more unsharpen at about 25 percent or so. I find this makes a sharper image than setting the size to custom in PW. But that is just my opinion. This resized image can now be displayed at about 600 pixels wide and still look pretty good."""

We have found that improved viewer displays are found by:

Adjusting your image HEIGHT to around 1000 pixels high,  then displaying them in a viewer HEIGHT of 30 to 35% of the image height.

So an image is 1000 pixels hight might look best using a viewer height of 300 or 350 pixels.

Of course we are referring to a java viewer like ptviewer.jar.  I have not tested the tourweaver java .jar.

Dave

Fatchai,

If I start with an image 4000x2000 and i want to size down to 2000x1000 that is a 50% reduction in size. If I sized down 10% each time it would take 5 steps to size down 2000x1000. The more the size reduction the more steps it takes. You could do it in 3 steps and that might work out fine. Its relative to the amount of sizing down. If you use too many steps like 5% each time for 10 times that would  make a crappy image as well.

A good rule of thumg is a 50% reduction in size needs 3 or 4 steps using between 5% and 10% of unsharpen  each time.

The point is to sharpen up the blur caused by the size reduction (ie interpolation). You are only tryint to counteract the softtening of the image. If it works out you end up with a smaller image close to the same sharpness. On the last step add a little more unsharpen  depending on the image. Sometimes you won't need to add any.

If you do a few images like this you will see how it works. Some do real good without too  much unsharpen other need a lot for each step.

If you just wipe out 50% of the pixels in an image the image will get blurry and contrasty. By doing this in steps allows for the image to progress to a smaller size in a more orderly  manner.

I wonder what effect screen resolution has to do with display size. A 800x600 screen has a 25% height size ( 600/800=0.75).

A 1280x1024 screen has a 20% height size.(1024/1280=0.80)

Gen. Lee

lee,

can you really notice the difference if you go from 100 to 50 in 1 step as opposed to going to 50 using 3 to 4 steps as u suggest?

Gen :

you mentioned that CP5000 and E8 are good combination. If i want to make full screen VR, what is your recommendation for non-DSLR camera ? (example CP5400 and E9)

tks

fatchai

hi Gen or anyone :

Can anyone direct me a web link or post a full screen pano by using

CP5000 and E8.  I really would like to know what is the quality like using a 5MP and E8 fisheye. etc...

tks alot

fatchai

fatchai,  gen lee posted one within the last 30 days. should be here in the panoweaver forum.  if i find it i'll post it.

you can search for 5000 and full

VT360,

The sizing down trick is for when you need to take a very large image and size it down to a much smaller one. Sizing down from 100 to 50 will not make any difference.

But sizing down from 2000 to 300 will. Or sizing down from 400 to 100 will. It is the amount of sizing that matters. Like wise sizing down from 2000 to 1800 wont make any difference either.

Now sizing down from 4000 to 2000 will make a difference because you are dealing with 2000 pixels of lost data. 4000 to 2000 is not the same thing as 100 to 50. They are both a 50% reduction but you will SEE the difference with the bigger image vs the smaller image where you probably wont notice a big difference.

Heck try it out. Use a good quality image at 3000 pixels wide and size it down to 100 pixels wide. You will see the difference. I haven't mentiond taking the image down from 300 dpi to 72 dpi. This has a even greater effect on the image. BUT......this is related to dimensional size vs dpi. They are all related. What you do to one side effects the other jsut like in math. Its all got to be equal so to speak.

Fatchai,

First it is well documented that most feel the FC-E9 lens produces a softer image than the FC-E8. The "optics" are where it really counts.

As an example: I have a D70s which is ONLY a 6 megapixel camera. The CP8800 is a 8 megapixel camera. BUT I use a kick A** lens...the Nikkor 10.5 mm. I will run circles around a CP8800+FC-E9 all day long with my D70s+Nikkor 10.5mm.

You see it is the optics that matter not the mega pixels. Don't get hung up on megapixels. There are other factors as well like wheter the CCD is a 12 bit or 8 bit device and the size of the CCD.

Megapixels of camera refers to only the maximum dimensional size the camera will produce. They all produce at 300dpi. The more megapixel of camera the LARGER the image will be.( I am excluding RAW images at this is anoter topic)

I know you are wanting an easy answer. But it just isn't like that. Workflow and your ability to capture a good bracket set with good tonal range are at least 50% of your final quality. You can really mess a great image up with a crappy workflow. You can have a good work flow and ruin the images with poor exposure and you will still end up with poop.

Have a look at this link
http://66.118.155.203/roebuck/meditarrenea/index.html

These images were all made with the cp5000 except the Master bedroom and living room which were shot with the Nikkor 10.5. These were stitched smaller and sized for 500x375) There is a full screen version of the living room to compare against. Here you can see the difference between what you get with a Nikkor 10.5 and the FC-E8. There is only 1 megapixel difference in the cameras.

Just for you  I am going to seam up one of these shots made with the CP5000 to full screen. I will post the link in a few minutes.

Gen. Lee.

Ok here it is

CP 5000
Hemi size is 2560x1920. 5 image bracket set at 2 stops. H&S-Auto in photomatrix. Stitched at 4000x2000 for full screen and 2000x1000 for 500x375 display. 90% compression for both full screen and 500x375

Note: i did not touch up the seam as this is for testing anyway.

Java 500x375) :http://66.118.155.203/360/cp5000/living_2000/living_2000_applet/living_2000.html

Qtvr (500x375):http://66.118.155.203/360/cp5000/living_2000/living_2000_qtvr/living_2000.html

---------------------------------

Full Screen
Java: http://66.118.155.203/360/cp5000/living_4000_2/living_4000_2_applet/living_4000_2.html

QTVR:http://66.118.155.203/360/cp5000/living_4000_2/living_4000_2_qtvr/living_4000_2.html

Gen. Lee